The older brother is valuable to you. But, no matter how valuable he is to you, he's still just your older brother. P.S. You'll often see some gangstah thug call a higher ranking gangstah thug (one that acts like an older brother to all the other gangstah thugs) this. It's like family within the gang.
The reading is 兄 on its own plus the reading for 貴. ANIKIIIII.
Your older brother is a really cool guy, but mine is not.