So you and he are "sharing" a vehicle. Is it registered in your name? Is the car insurance in your name? Whoever's name is on that title is the owner. If he gets in an accident, while he is driving your car, then your insurance rates go up. Something's wrong with that picture.

It sounds more and more like you didn't lose all that much, when you lost him. A man his age can't provide himself with a vehicle . . . can't even keep adequate groceries in his kitchen. This sounds like you divorced a husband, just to turn around and adopt him as a child. How much of a father can he be to your son? You're going to subsidize that relationship to keep it going? So that your son can have this important role model in his life, so that he can be more like his daddy? That's what you want?

If that car truly is yours - legally speaking - then it should be kept parked outside your door. Should there be an emergency for your son, or you, that car should be readily available. Are you lending it to your ex because he has no way of getting to work without it? That's a problem for him to resolve. Don't worry, he will. You won't get down to solving the problems that are legitimately yours, while you are solving problems for the ex. He'll figure out how to get around and how to eat, if you leave those problems on his plate where they belong. Type 2 diabetes is usually the outcome of a long span of poor self care. If he runs out of groceries and misses a meal or two, that could benefit his health. Type 2 diabetes comes from eating too much, not too little.

Whether or not your son will have a father is largely outside of your control. Let go of what is not in your control. Focus on what kind of a mom your son has. That is what is your responsibility. Having two parents who are both confused about who is responsible for what is detrimental to your son. It will make him insecure and give him no role model worth emulating. Sooner or later, your son will have to come to terms with having a father who is not responsible. If he knows he can depend on you, he will be able to deal with being disappointed in his father. Your relationship with your son is what you have control over. Sometimes, it is actually better for children to see less and less of a parent who is not fulfilling their role properly. So don't try to manage things so as to create a fictional father who does not exist. Your son needs to understand the reality and not keep hoping for the father you want to magically create for him. You mean well, but you'll get an outcome that you won't like. Lots of children grow up just fine missing one parent or the other. The main thing is that there be one left who has got the act together. (That includes a mom who, if she owns a car, has it at her disposal.)

These "deeply ingrained thoughts" have a better chance of getting changed, if you accept that you are divorced and cut down on a lot of inappropriate involvement with your ex. It is understandable that you are still having a lot to adjust to, since the divorce is very recent. However, there won't be a better time than right now for starting to separate your identity from that of your ex. It's not going to get easier by waiting. He has already moved on to other women, if I remember right. Let him find what help and support he needs from the new woman in his life. If there is no woman at the moment, then that is his problem. He didn't value his marriage to you, and it's now over. There are consequences to that, which he will have to cope with. He can't have his cake and eat it too. Your conversations with him should be business-like for the purpose of co-parenting. They should be brief. Actually, if the judge gave you full custody, I'm not sure what kind of co-parenting is going on. Your son is watching all of this, and he must be having a hard time making sense of it. Keep it simple.