Friends you wish you could help.

Last week I was with a friend and he was telling me how is ex-gf was nuts, like crazy nuts well as it happen they hadn't talked in 4 months and that night she calls and wants to stop by. I agree that I should leave. Nope I didn't and I got to meet the crazy-ex. Now everything was so pleasant that night however in the week following I have tried to talk to him with no such luck.  I do believe that they are once again together and I am a little worried for him. He was going on about how he really wanted to just stay away and now they are together and that. Well you know what he is a big boy and he can do what he wants. why do I care?