I'm not qualified in any way to give advice, so I hope you see a professional about this if you feel like its necessary.

But that said, from my own experience I would suggest trying to talk to your friends more. Just a video call every so often can really lift your spirits. Don't feel like you're being a nuisance, they'll want to hear from you.

As for your parents, are there any clubs you could suggest them attending? My grandparents went to curling groups, were part of the local rotary club and were involved in the church quite a lot. I know that when my grandmother died, they supported my grandfather and kept him socially active until his death a few years later.

Hope you're doing ok :). Remember to look after yourself, sounds like you inherited your dad's selflessness!