At least he has some sense. I get that there are wastes of gas, but I think that's a choice you make and have to live with when you don't live close to your significant other. It's like when people date and live in different countries, if they want to see each other they have to accept paying for a few airplane trips- there isn't much of a way around that. He's saving money by living with his parents and his parents should realize he could have moved out for freedom's sake.
Honestly, I would probably offer to split the price of gas when you guys visit each other... if you go he pays half... if he goes you pay half. It seems pretty fair since the visit is for both of you and I hope his mom can't complain about equality. Also, if this situation is going to get worse with you moving you guys might want to look into one of those gas reward credit cards... might as well save where you can.