Is at the end of his tether - Idioms by The Free Dictionary
be at the end of (one's) tether (redirected from is at the end of his tether)
be at the end of (one's) tether
To be completely worn out, exasperated, or exhausted; to have no more patience, endurance, or energy left. Joshua started throwing a tantrum this afternoon, and with all the other things I have to get done, I'm at the end of my tether!
be at the ˌend of your ˈtether (British English) (American English be at the ˌend of your ˈrope) having no more patience or strength left: After two hours of hearing the children shout and argue, I really was at the end of my tether.