I had a messy breakup a few years ago with a guy who was retroactively diagnosed with bpd (we thought he was bipolar). It was an extremely difficult time as he is not from this country so I was caught up trying to link him and his family post-breakup to get him home. 
The details of the breakup are somewhat irrelevant now, but it ended with my cutting contact completely as two efforts to talk things through after the breakup ended up in his being sectioned. So it seemed safer to stop speaking. 
So 3 years have passed and in that time he has sent me an email almost monthly, journaling what he has been up to. I’ve not replied to any of these so he doesn’t know if I even received them. 
He is now happily engaged to the wonderful girl he has been dating for 2 years+ and I am very glad for him. 
My problem is that he is now trying to reach me by text message. I’m inclined not to reply as I don’t want to rock the boat when things are seemingly going well for him. I just don’t know if replying might give him some peace that he’s been searching for. I spoke with his mum and she said he is not the same person, so doesn’t advise for or against replying; it’s up to me. 

I’d like to hear from men 30+ in particular, as to whether I should reply or hold strong in my silence.