Well, as someone who is a coach and who was a hothead, I guess I can't say a whole lot. I have had my tirades, but I have grown up. What bothers me is a) alcohol was involved and b) he was complaining about seating. Holy cow! Is the guy OCD or something?
I'm like everyone else here. I do not put up with alcohol-induced tirades. If you can't handle your booze you either should not be drinking or you need to have your hindside firmly kicked - many, many times. The last two people who went on an alcohol-induced tirade in my presence were my ex brother-in-law, who nearly met his demise at my hands and a loudmouth idiot who came out of the lounge drunk off his tail who was promptly escorted back to the lounge by yours truly and two other adults.
Back to the point at hand, unless that man was acting in the capacity of a coach, he is "untouchable" as far as his coaching credentials are concerned. Yes, he is a despicable, loathsome, sorry excuse for a human being (and coach), but it is up to the league at hand and to the management of the bowling center to
deal with him because his actions were outside the scope of the junior bowling league and/or a function where his capacity was "coach", not paying customer.
But, you may have some recourse as per USBC Rules:
115a. Dismissal of a League Officer or Player
A league member can file a written charge asking for removal of a league officer or dismissal of a player.
1. A player may be dismissed from the league or an officer removed from league office only for any of the following reasons:
a. Conduct derogatory to the best interest of the league.
b. Any deliberate action which can be proven to be detrimental to the best interest of the team.
c. Violation of any USBC or league rule.
This one's a bit of a stretch, but possible:
17b. Improper Conduct
An individual can also be charged with the following violation(s):
1. Engaging in improper tactics or conduct in connection with the game of bowling including, but not limited to, physical and verbal abuse toward other persons.
I'd highlight those passages, show them to Mr. Hothead and see what he has to say for himself.