my family is a mess and I don' know what to do

If you're 'very concerned' then you need to report your worries to Social Services.

I am not trying to fix things and my contact is minimal I see no one and live alone, they are my bubble but I hardly see them.
I am the one supporting them. They see no one either- the four of them are stuck in the house together and never go out.
I am not anxious about Covid but about the baby.
Yes, it is up to him to sort his problems but can someone support me?

a whole heap of problems- don't want to list them as they are complicated
I live alone- he is not supporting me at all
he is financially independent
he lives with his partner and her adult son and yes, I am very concerned about the child.

It's not up to you to fix things - even if you could. Surely, right now, you want to minimise contact anyway?

Support bubbles are optional. Do you really need any help from them?

Safe contact, by phone, Zoom etc. would reduce your anxiety about Covid risk.

Look after yourself first, be a good listener - but it's up to your son to deal with his family problems.

maybe some more detail would help.
what is the problem.
is he supporting you, or you him?
is he a single parent ?
have you any concerns re the child ?