My advice....scream!

No seriously, he probably needs the help of a grief counselor. He has lost much and his car dying on him is the last straw. He feels as if life is working against him and is 'pouting' about it. Men grieve differently from women. They tend to turn it inward and that's where it often stays. Then, it brews into other issues, rarely are what he'll admit to bothering him and what is really bothering him the same thing.
Men tend to want to fix things and if they can't, they often feel helpless and worthless and the cycle continues until they can't pull out of it.
Will he consider seeing a grief counselor? Or any type of counselor? Even if he joins an on-line community such as this one, it would help him. Please step carefully because he is grieving and there is no time limit on grief, but when it becomes destructive it's time to take another road and get the help needed to deal with it.
Asking for and accepting help is not a failure, few people are equipped to deal with grief, let alone so many losses at once. The ones who can cope without the help of others is few and far between...maybe they're just better at faking it than others are.
Let him know gently that there are some things in life that aren't meant to stay bottled up inside and that he doesn't have to confide in you, but he does need to confide in someone of his choosing...and then honor that. He may want to keep you out of it because he's afraid of what his emotions and issues might do to you or would be hurtful to you.
Just keep nudging, but do not judge him or he'll keep shutting down.
Also, get help for yourself or find someone to confide in because this also effects you and you need and deserve the help to cope with this. Best of luck to you both...if you stay strong and keep the lines of communication open, you will make it through.