Hi across the pond, I think our children like their privacy, even on social media, I comment on my daughter's sometimes but choose the post carefully or she may feel I'm snooping on her, so don't comment at all.  It's difficult when they live away but you could try Messenger or WhatsApp to post and these are private.  Just persevere with him, my daughter had a hard time after the birth of her second child and I was always the Brunt of her anger and it was really hard as we had always been close, but this took four years to sort out and the change came when her Dad was diagnosed with cancer.  So hang in there, write chatty letters and ask how he is doing, tell him what you have done, don't moan or complain, he is trying so hard to overcome it all, just be there for him.  Sending a virtual hug your way, Carol x 

Your sons had brain surgery, sometimes these can change a persons personality, just something to think about as you said its only since his operation thats hes changed.