Dear C.,
How wise that you recognize this situation needs some TLC! This will be long too, but lots of ground to cover. First, let me say, I am not in agreement with the way your in laws are treating you and your family. But you are not responsible for what they do, that is their problem. You are, however, responsible for what you do as being part of the solution. Your kids will not focus on the negative if you redirect them to some positives about Grandma and Grandpa. Show them the positive and don't allow them to hear you and your husband talk about the negative.
Your hubby and you as his wife have to do the right thing "honor thy father and mother" even when what they are doing may not line up with your expectations. (As long as nothing illegal or immoral is going on of course!) He's got to get it right with them or at least try to show them love so he is not carring around a burden of should have, could have, would have after they are gone. Also, the degree we honor father and mother has a lot to do with the way our children will or will not honor us. If you don't help him get this right now, you could have one miserable hubby on your hands one day. You love him so you don't want him to walk around feeling guilt or shame so you have an opportunity NOW to get it right while his parent are alive!
Look for a moment from their perspective. Put yourself in their shoes as a parent. If you are a Christian, and your child strays from Godly principles, it is less a matter of pride, but more a mattter of love to try to win them back to the Lord. We all want the absolute best for our kids. And that best is knowing our children are walking in a relationship with Jesus every day. (That we can praise Him in the good and bad times and that we know the power of prayer, learn of his grace and know the promises He has for us...to name a few).
Like the previous post, I also question how they would allow their son to leave the chruch at 13 when they were the parents and responsible for their son! This one is huge. What would the world be if we let every 13 year old make decisions on what was best to eat, drink, and do each day? Perhaps they realize their mistake here and are trying to correct it a little too late, but they have some unfinished business here.
I must say their "method" may not be the greatest. It doesn't sound like a way to win someone to the Lord, or to going to chruch at all. But because they are human, they have made a big blooper here. They've obviously made some mistakes. But in life we can only move forward, so you must face this head on. All of us make mistakes in relationships and we fail. But we always have the next day to get it right. I believe that is what you are really hoping to do is to just simply "get it right."
Do you have your own church? If so, share with them the things their grandchildren are learning and doing in Sunday School. The ROOT of this is their are afraid that since they only know "their religion" that your hubby has walked away. They want you and him and your children to spend eternity in Heaven with them. Since you said they are praying for you, I really think that they just fear for you and your husband and kids and where you will end up in eternity. Their comfort and peace would come with knowing you all would be in Heaven with them someday.
Jesus was love, he walked in love, and talked in love. Plant some kind seeds of love in them, even if they don't deserve it. Teach your kids to be kind, loving and respectful, even when it doesn't feel right and then tell them why, because the greatest commandment of all is to love one another as God loves us.
We reap what we sow (another biblical principle). Again, I am not saying the grandparents are doing things right. They are trying to get your attention about their chruch in the wrong way (by treating you as less than). I just say plant some seeds of love their way today and you will get love in return! If they are assurred of your salvation and that you are teaching your children about God, then they will feel much more comfortable. (This is why they are praying so hard for you!) The real thing they want is assurance that you will all have the gift of eternal life that God's word promises.
People with deep religious convictions really want the whole family to end up in Heaven someday, they want no one left behind, especially not one of their own. If you know Jesus as your Lord and Savior, let them know that. It isn't about going to any one church in particular, although many families feel whole if they have all their chicks in one nest. Relate this to your own kids on Christmas when they are adults....if they can all make your family gathering how wonderful it would be...and the void you would feel if just one of them couldn't make it. (This is, I'm guessing, sort of how they feel with their family so split up).
Because they love you, they are trying all they know to get you to stop and think about eternity instead of just today. (Again, their method isn't pretty, but I really think they love you so much they are trying to get your attention). They kind of missed it when your husband was 13 and now they have realized their mistake and are trying to discipline him now. It's not working because he is an adult. It would be great if you could all have a long talk about it. Spill all of your feelings (in love) and let him do the same. Also let them know (if you can) that you can forgive them for any mistakes of the past. And then let them go. Regardless of what is going on, these are your husband's parents and your chidlren's grandparents. Model love and respect to your kids by showing love and respect to his parents.
Churches are much like families. And many families have the tradition of all attending the same chruch. My guess is this was the case for your hubbby's family. As backward as this may sound, they love you so much, they are trying to get you to stop and think about coming to church. There are many blessings being with like minded believers each Sunday. Church life is a lot like family life and people do all they can for one another. We are also encouraged to go out and teach others outside of the chruch as well. I know what this looks like and I know what you are feeling. I would NEVER want to be pushed into any religion.
However, as a parent, if you don't have a church, I think it may be a wise thing to do for your children, your hubby, and you, even if it is not the same church as your in-laws. Also you said your hubby said you and the kids are his family now. That is true, a husband is supposed to make a new life with his wife and kids. But he still has parents, and those parents still NEED his love and respect, even when they aren't doing things the right way. Because they need your love, you can both feel the peace of doing the right thing if you visit regulary and show them a little kindness and love, even if they don't return it. This will also teach your children much about kindness and love. And you can keep your husband from experiencing negative emotions later if you get this right now.
I hope in some small way this helps you see where they could be coming from.
Blessings!
E.