Nancy my answer/suggestion is similar to this.
Ask your Mom to call him (that way you don't have to worry about calling him and possible getting his GF), and tell her to tell him that you're coming to visit her for a couple of days and you would love it if you could get together with him for a coffee, and just take it from there, extend the invitation to him, meet with him, and just start talking, he is your brother you miss him, and I'm sure he misses you too.

