Hi and welcome, manda-xo!
I'm a non-jw with some friends and family in, and cannot even maintain regular contact with my two jw "friends", so don't know how helpful I can be.
I'd say whether your BF can maintain contact with his jw family will depend mostly on how hardline they are, rather than on him. This religion is quite effective at breaking up families, unfortunately!
Perhaps geographic distance could help; if his family doesn't constantly see him living a non-jw life it might be less of an irritant.
Most importantly, if you plan a future together, make sure he is really free of jw thinking and there is no danger of him reverting to the religion he grew up in. Keep reading here and you'll see exactly why. It's important that you understand the issues also.
Best wishes, and hope you stay around, Retro