I don't think you should marry him, even if we forget about the assets you have being at risk.
When it comes down to it, your values are very different. You believe in working hard and being independent. He thinks that he is entitled to have what he wants immediately without having to work for it.
In a marriage that sort of incompatibility just doesn't work.
It doesn't sound like he is able to be what you need. He is thinking about himself at a time when you need support. The problems he has are of his own making, and he can help himself out of them, if he changes his attitude.
You need to have a Big Talk. He will have to change a lot before you can think about committing to him, and you will have to see if he wants to, or is able to. He doesn't sound happy with the way things are. He might want to be different. You can't change him but you might be able to support him while he does.
At 22 I think I would be inclined to pull back and see how it goes. The world is wide open to you.
If you love him then you have a lot of time to invest in him, but I certainly wouldn't let him near your money, and definitely don't marry him.