<p>You don’t know the back story. It may be that the cousins have been jerks to their kindly old father who just wants a little human touch; it may be that what you think of as kindly old father might have been horribly abusive, said things that hurt deeply, or otherwise “deserved” his estrangement. I would leave it alone or at most ask if they wish to be informed if you visit uncle. I agree with poetgirl, there are often real reasons for estrangement.</p>