My guy friend changed his number and now nobody can contact them

I have a guy friend and things are honestly great, one of my best friends without any doubt. Things are in a strange place right now though because they recently changed numbers though people do not actually know this, so nobody can text or call him. It is the darnest thing. I really wish it were possible to have a basic solution to something like this and merge the new number to everyone's contacts easily though it appears there is not a solution. He is not really a social media guy.

Any ideas or advice is appreciated because at this point I don't know the correct thing to do.