May need to find birth family for very ill friend.

I have a friend, Bob, who was adopted in the 50’s. His parents are deceased and he has no other family. I’m pretty much the only one who cares about him. He’s had lots of health problems and is now in the hospital with pneumonia and sepsis. I’m afraid that he’s not going to make it. A few years ago he made contact with some of his birth siblings, who were all also adopted, and he met his birth mother. He had contact with a brother and a sister for a while but for some reason it didn’t continue. I’m having two issues I’m pondering. The first one is that his siblings may want to see him if he takes a turn for the worse and it doesn’t look like he is going to pull through. Should I bring this up to Bob or is it something I shouldn’t interfere with? The other issue I’m wondering about is if these people should be located and notified if Bob passes? If so, how would I locate them without any info from Bob? Would it be out of line to ask about that? I know it’s a sensitive subject. Any input would be appreciated.