When is hard work not enough anymore?

My boyfriend is really struggling with college. He made some bad decisions and ended up racking up $30k in debt before finally deciding what he wanted to major in. He confessed that he never thought about it because he was extremely depressed before he met me and wasn't planning to live that long. (He has clinical depression and is mildly on the spectrum) Unfortunately, it's going to take him at least 2-3 more years to finish and having extremely limited funds, he needs to be supported heavily. (For example, living rent free so he can work to pay tuition and do well in class)

Now, he's been trying really hard to be improve but I recognize that he's not at a point where I would want him to be as a partner. My family keeps pressuring me to leave because they dont think he's good enough and can support me financially.

It's terrible and feels invalidating to know that you tried your best and that it still wasn't enough. I'm still with him because I love him and recognize the efforts he's made.

We've been together for almost 4 years now. He's said multiple times before that he would like to get married. As I'm on my last year of graduate school, I'm feeling the pressure and don't know what to do because I love him but I dont know if he can support me or our future family despite trying his best to make it happen.

When is hard work finally not enough for a relationship? Or is it enough to make a relationship work?