So much for not knowing what to do when he isn't with us. I knew I shouldn't have said that. So just when we thought things were stabilising, he gets an ear infection - but the only way he can tell us he's in pain is to fit - until the infection bursts. We now know what the matter is (I think) so we're treating him with antibiotics and pain killers - seems to be working, in the sense that he's sleeping and not getting too distressed.
This is really what difficult communication is about - it's not difficulty in telling us whether he'd prefer a bath or a shower, or which clothes he wants, or doesn't want to wear - it's about being able to treat him for extreme pain when you don't know he's having it or what's causing it. Being non-verbal isn't a problem, it's a major disability in its own right.
I've had earache from an ear infection and it makes me feel literally sick to know he had that sort of pain before we could do anything about it.