How about something like: Are you upset? Do you want to talk about it?

Or: You can call any time, even just to say hi!
Oh no, I can't call at all unless I check first to see if my dad is on call. I don't know why he can't use a work cell phone or second line...oh well, my mom is annoyed if I call for no reason. So guess what? I don't call. We email sometimes, so I guess it's not like we never talk...