How do you know if you qualify for the Covid vaccine if you have health issues?

My husband found out he can get the vaccine and we are both on board with it so long as it’s not a risk for him to get it. He has several chronic illnesses and sees different specialists for them. He also has a general physician.

I read when the shots were initially given that they can be risky for some people with autoimmune problems. I know it’s riskier for him to catch the virus but I’m terrified he may purposely put his life at risk if he gets the shot.

How do we find out if he should or should not get the shot?
I’m also not clear about whether doctors know enough about the shot to actually give a qualified opinion.

Is there some site or someone we can get information about the risks for people with certain ailments?