Is it normal to ruin your friends life over an ex girlfriend?

A buddy of mine asked some people to come visit us while on vacation for the weekend. An ex girlfriend he might see once every blue moon and one of his best friends he hasn't seen for awhile.
So the first night goes as he planned and everything was good to go.
Next day, he told us that she needs to be taken care of when she get intoxicated from getting to wild. Me, him and his best friend, go down to the heated pools to recuperate from the previous night. While we are down there he starts talking to girls staying in the same resort that we are staying at, and want them to go out with us that night. I asked him what he was going to do about his ex he didn't care what she did. A quote from him was " you can have her". so i asked him a second time "so your telling me that you don't care if i got with her tonight and you wouldn't be pissed with me" he said naa man go for it. Well his best friend was right beside us in the pool and heard all of this as well.
So as the day goes by we go back to the room, everyone has drank and sobered up at least three times already. At this point she is flirting with all of the other roommates, and he isn't saying anything about it.
Five of us including the girl are left at the hotel and go out walking to see all the decorations and band for st.patty's day. The best friend and ex go disappear in the room with the door locked being loud. The Ex bf is gone at this whole time. So we leave and go out to the clubs. As the night goes by ex bf calls to see what we are doing. they are still at the hotel. I guess his night was ruined so he and the other guy didn't go out that night.
Midnight comes along and we get a call from the ex and Best friend and they want to go out, so we hit up a dance club and then a strip club for the last night out cause we are leaving the next day. The best friend told us that that they couldn't go back to the hotel, but they didn't have any money to get a hotel for the night and was too drunk to drive. So me being one of the room payers told them they could come back, but needed leave first thing in the morning.
Well i wasn't the dd so i slept through the screaming that went on that morning and the end result was this.
The ex and friend fell asleep on the fold out couch. i guess it began to get loud in the couch area and the other friend heard them and flipped, and kicked them out right there and then. So them being good friends he knew that the guy that slept with the ex was going through a divorce and custody battle with his 2 kids. He was still pissed as hell and said screw this I'm gonna ruin his life and get his kids taken away from him, calls the best friends wife and tells her that he will go to court with her and testify on her behalf.

So is this normal or did he go overboard in anger?

If i wasn't clear on something don't hesitate to ask because im kinda at a lost for words on this one.