A.,
Your family didn't manage to put you in debt. You and your husband made poor choices, likely knowing their situations, and managed to get yourselves enmeshed in their situations.
One of the hardest words for some of us to learn is "no".
My guess is that your husband is holding out hope that sometime, somehow, he's going to get something from his family-- some sort of validation-- that he's been missing since childhood. My guess is that this informs his choices.
Without going into details, I also had a childhood and partial adulthood which could be described as hellish. As a child, those needs I had which were never met-- I still kept turning to the same emotionally-bankrupt people to fill them. That was MY mistake. What they could not give me as a child they most certainly did not have to offer as an adult.
What I can also speak to, however, is how incredibly scary the potential of being permanently cut off is. I chose to end contact with a very toxic parent and it took me a long time with lots of counseling to identify how bad the situation was, how I was choosing to stay in a dance of dysfunction with the parent who was still damaging me, and to work up the self-esteem to see that I could make the choice to demand more (in this case, counseling with the parent) and deserved to be treated better.
This took about 2 years of counseling before I got to this point. And when I did, I grieved it like a death. It was, in some ways-- the death of having hope that this primary parent would love me for who I was, without all the hoops to jump through and conditions which made the relationship so sickeningly unhealthy. It was the end of wishing I'd had a better childhood, accepting that it was never going to change, and accepting that I was going to be persona non-Grata for the rest of my life with that part of my family.
I also had to accept that, in closing that door, I lost my own voice with some of the people I loved. That parent decided to tell everyone that I was mad at them because they didn't give me a present. No joke. 12 years later, this is still the 'reason'. Sometimes, bad blood is just going to happen and you have to accept that it's better not to be engaged than to continue to re-engage and trying to clear my name. Only more nonsense really, and for families which seem to churn with nonsense and drama, 'making nice' will mean being sucked back into it.
Your husband will need a lot of understanding and unconditional support as he moves through these different feelings. One of the worst things my (then, now ex) husband said to me at the time was that I needed to just 'get over it'. While I was a 30 year old grown woman on the outside, there was still that sad little kid on the inside who was mourning the love she couldn't ever get from that parent. It is a terribly sad state of affairs to see that your parent/family is not capable of loving or caring in any sort of healthy way, and that the ways in which 'love' were given were so incredibly damaging-- that takes a lot of time to heal from.
So, know that this can be like a death, it can be a huge heartbreak to admit that no matter what we do, we cannot *fix* our parents or siblings. Focus on what you can fix. Perhaps couples and/or individual counseling will help. Yes, we as married adults should always put our own family's needs first, (or course, there are catastrophic circumstances, but lets just go with the usual stuff here) and your husband is going to have to come to a place of accepting that his family can't be fixed by him alone. He'll also have to accept that HIS love cannot make them be more healthy or loving, and accept them for who they are and what they do or don't have to offer.
Sorry this is so long, I just wanted to share that it is possible, but indeed painful, to move forward. Please have a lot of compassion for your husband as he moves through these emotions and find some outside support so this doesn't destroy your own family.