Help! Parent of young adult

Hi, I'm new here and this is my first post. My son whose 19 was diagnosed this year. He started Uni last year and is living away from home. He has always struggled with friendship in the real world but not on line where he has several good friends who he has met with. He is really struggling with maintaining friendships at Uni although he does seem to have a couple of people. 

My question is how do other parents support their adult child when it comes to friendship. He is saying he feels lonely cause they aren't always including him or responding to his texts. It's difficult to tell whether this is his perception of the situation or whether they are only tolerating him which is heartbreaking!

As a parent it's hard to hear and it would be good to have other parents experiences of helping their young adult child.

Thanks and sorry for the ramble!