He's your biggest fan (arguably next to your mom).
1. He always brags about you. If you get a promotion at work or even just win concert tickets he can't resist telling everyone you hang out with before you even think to mention it. Because he's your biggest fan (arguably next to your mom).
2. He makes sacrifices for you — and you're happy to do the same for him. He'll move cities to live with you if you get a new job or finish grad school. You're happy to make the next move for one of his opportunities.