Belle as Masterofnone said, it does get easier. Mr7 gets very frustrated with himself to the point of meltdown too.
When I'm not going mad (I feel your pain) humour has worked wonders for him (us). One example I can think of is when he's make a mistake and is on the downhill spiral, I rushed into a door way and pushed against the sides, looking up at the ceiling and calling 'Take cover, take cover!' It was enough to distract him into stopping and asking me why?
I told him he make a mistake so the roof must be about to fall in! We waited....and of course nothing happened. He had a giggle and just mentioning it a few times since has stopped him in his tracks. It also enabled us to have a few discussions about everything that could possibly happen to him because he made that mistake - the answer is usually not much!
Hang in there!
