Bones -
One of the things he has a habit of doing is completely ignoring things that he does not consider important to himself until I finally start yelling at him.
Send more info - "ignoring things that he does not consider important to himself" - sounds like he has a bad case of maleness.
"until I finally start yelling at him." - not the best solution as it leads to the dread disease of screaming meemies.
Seriously, something he's not doing is clearly driving you nutso. But is his behavior irritating or over the top in self-centeredness. The screaming solution is one way to get action but I suspect if you thought about it you could get similar results without dragging yourself into the mire. Take it from one who has recently recovered from being angry and raging for years. Life really is better without screaming. In fact if you practise on past experiences and think of clever ways to prod it can become an entertaining challenge but there is also a middle road method to getting the actions you need.
Give a "for instance" - made up or real and lets work it out for practise. - your friend - Gaining strength