Your dh should forget about collecting on the bill BUT dump the friend. He can't force him to pay but the fact that he flat out refused says tons about what kind of a friend he is. He sounds like a total user. I'm sure you'd love it if dh could pay $3 a day to have a ride back and forth to work - this guy thinks he's "paying his way" but he's not. Man, who wouldn't be happy to be chauffered around for $60 a month!!! But if you can't get your dh to insist on the payment or stop the chauffering, I would drop it because it's not doing you any good to be pissed at dh. Maybe he's just a good enough friend and conversationalist or maybe he's just dh's charity case but I'd seriously drop it because this guy isn't worth your marriage. $90 isn't worth destroying a marriage over either. But no, you are not being a butt. Just sometimes it's just not worth it to be mad. The guy's a jerk but it doesn't sound like your dh is doing anything really wrong other than being used and it's probably hard on him to be in the middle.
I hate that the glass broke since I know it didn't get it all but at least it forced me to sweep, right?!! :-)
I'm going to keep drilling. Just knowing there's a possibility you might see my lists even if you don't respond makes it easier for me to drill for some reason!