Reading the various posts, I can see that many sever contact with parents for different reasons, the parent might have intentionally hurt them or not given sufficient support for various reasons and hurt their child, however old he or she is. What I ask of you is what does a parent do, who loves and misses them do to make amends. If you tried to find out unsuccessfully before the estrangement and was met with hostility and a refusal to talk, it is very difficult to know what to do without seeming intrusive or an interfering pain. When they estrange themselves and get on with their lives, is is wrong to try to put it right, to make contact, if so how, or is that going to upset the son or daughter
and make things harder for them. Know there are a lot of bad parents out there, also a lot that not intentionally useless but must have got things wrong.