Would you let a family member who's terrible with money move in with you so he wouldn't be homeless?

No.  No.  NOOOOO.

This is not a dad obligation.  This is a MOOCH and a low-life.  He doesn't care about you or his son.  He wants a cushy life.  

Oh and by the way?  What the heck is in it for you, besides headaches?  He will certainly cause you problems.  I promise. I also promise you that you will not be able to get rid of him, he will drive you up the wall and keep pushing and pushing you till you think this is NORMAL.

Do NOT let him step one foot in that door.  If he is homeless. TOUGH.  He can figure it out. He is a big boy.  If I were homeless, I would not be homeless for long.  Maybe a few months. IN the mean time I would find a shelter and focus.  That's what daddy needs to do.  Something he has not taken care of his whole life.  RESPONSIBILITY.  It sucks.  I know.  Especially when you are a person who is dumping your responsibility on your kids.

He doesn't realize this, but you are doing him a favor.  

Wow, talk about being between a rock and a hard place. 

Hubby, take the Randy D path: let Pops badmouth you to high heaven, but under ZERO circumstances bring him into your home, not even temporarily. 
Pops has to sell his car, take whatever profits there are, no matter how meager, and get a tiny studio apartment in a senior living complex. 

~

It would depend on many other factors such as
whether the family member had a disability that made him or her dependent.
I wouldn't accept anyone who had any tendencies towards violence, manipulation, dishonesty, gambling or drug addictions.

It is possible to accept difficult family members if one sets good boundaries - preferably written and signed with clear and immediate consequences if an agreement is broken. It means arranging means to make it impossible for rules to be broken - like no access to other people's money, good locks on doors and so forth. It means having a plan-B place for the family member to go if things don't work out.

Adults are not irresponsible for no reason. It's always a symptom of something else - maybe the end result of a chain of other factors.

For instance, your husband's father might have suffered his whole life from undiagnosed ADHD. The temporal lobes are up to 30% smaller, with small nerve fibres and fewer fibres in each bundle of nerves. This affects the executive functions of the brain; the capacity to pay attention is impaired, not consistently, but chronically, erratically every few seconds or less. This affects memory, working memory, planning, decision-making, inhibition (ability to stop or change at need), impulsiveness and risk-taking.
It can be diagnosed and treated.
And because the brain is neuro-plastic, there is no age at which developing coping strategies cannot begin.

Do you get on well with your father-in-law? What about other members of the family?
If he did come to live with you - I think he'd have to agree to respecting the rules of your household.
And he'd have to be aware that he's no longer in a position to play Dad, Patriarch or Boss - including guilt-tripping.
Would probably be better if he could have a separate room or studio-flat.

This car that your father-in-law is buying - would it work as a place to sleep?
Would he do well in a camper-van? Could he afford camp-site fees? This post was edited by inky at October 1, 2019 4:37 AM MDT

If that family member is a good person in general, practices good hygiene and respects our household standards, can contribute to our common effort in some positive capacity, and most importantly doesn’t bring unwelcome baggage or conflict into my home, there is a chance I’d say yes. Nothing challenges a relationship like cohabitation. 

In the example you give, absolutely no way. I will not be guilted or bullied into surrendering my sacred living space to a disagreeable loser who believes they are entitled to sponge off of us. 

I'm with Randy. If hubby's dad was just a born loser with zero assets, you could consider it - but he's spending money on a new car.

I most likely would, unless the person was an actively using addict/alcoholic  or has proven to be unsafe in some other way. I've spent too many years living with people whose behaviors induce fear, and I'm not going back there. 

Under the circumstances you described, no I would not.  What is he going to say about your husband - that he refused to subsidize him so he could afford a new car?  Let him.

Your husbands doubts are there for a reason, he should trust his instinct. As the saying goes "If in doubt, leave it out."

It's not a good idea to do something because you feel guilty,  because you are then doing something not because you actually want to do it and have a good feeling, but because you want to avoid a bad feeling, and that's dishonest.  In doing something to avoid feeling bad, in this instance you could end up feeling worse, you could end up feeling resentful. This post was edited by kjames at September 30, 2019 8:50 PM MDT

Yes and no. I have done so in the past and I would do it again even though it's a terrible idea.

However, I wouldn't do it under the circumstances you describe. At least the way it works here, and from what I've seen with those I know, Social Security is not enough to live off. It would work if you've got your house paid off or are renting a really cheap room somewhere, but otherwise, you're choosing between shelter and food or paying the power bill and food. New car or not, it's not enough to live off. BUT, here, those circumstances usually qualify people for things like housing assistance. He could either get free or subsidized housing in a traditional apartment or, depending on circumstances, may be able to get into an assisted living situation where they provide the meals. Since those options are likely on the table, I probably would not let the person move in.

Yes I'd feel obligated to do what I could to help out.  I wouldn't let it go beyond the means of my own immediate family's survival though.