C.S.
Hello,
First, tell your son that you would like to offer to help your daughter-in-law and ask him if that would be okay with him. Since they are not together, please respect your sons wishes. Then, assuming your son is okay with it, if you truly want to help, ask your daughter-in-law if there are things that you can do to help her. Try to be specific in the things that you can assist with. When my MIL offers to help, I'm never sure if she is really willing to help or just saying it. I saw from your blog that you are very into cooking and health food - perhaps you could offer to make a meal or two and deliver it to her a couple of nights per week so that she wouldn't have to cook on those nights. Perhaps you could offer to babysit so that she could have time to grocery shop, do errands, etc. If she might appreciate a subscription or two to a parenting magazine (not as a criticism but as a gift - something to read after the kids have gone to bed) perhaps you could buy it for her as a gift given of love, again, not criticism. A major help to me is when my grandmother has offered to come to my house when I'm at work and do laundry for me - she does the laundry and leaves it folded on my bed. A huge help and blessing!!! She never criticises the stains - just does her best - she never tells me that my son is hard on his knees or has too many "potty accidents" - she just tells me that she is glad she is here to help.
A last bit of help you might offer is if you know that your grandchildren need something (outgrowing car seats, need boosters, etc) and you can afford to purchase.
Try to keep in mind that virtually every mother, your DIL included, is doing the best they can do given their particular circumstances. If the children are not in danger - you are best off offering concrete assistance. If you criticize you may jeopardize your access to the children and I think that children need as much family support as possible.
Just my 2 cents...good luck. C.