I think its good to have some extra contact with him. Eg Skype, video call. At least you would see him and see how he’s coping.
Perhaps look into what support is available for him should he ask for it, at least you’ll be prepared.
There are people in recovery on this forum too, Perhaps they could suggest some help.
Danman83 suggested some podcasts and videos from recovering addicts. I’m sure he could google them. Online NA or C A meetings would help too. He’d meet others in the same situation.
Its a worry when it’s your child, but let him know you’re here to try to help as best you can.
Sending you hugs
Lx