You will continue to go into debt every week unless you fire him. It's like a band-aid - it's easier if you just rip it off as fast as possible get it over with rather than prolong the pain.
$55k is way too much for a your current situation. My suggestion: Keep him until the last training update before the playoffs, sell him but don't replace him until the new season starts and just train stamina/free throws for the playoffs/off season so that the level 1 trainer won't hurt.