A summer haircut without the sun

Raffy hates having his hair washed. He is very sensitive to having anything done to his hair and dislikes   being wet. In fact, he seems to crave 'dry' as a sensation in all areas. To the extent that he would hardly take in fluid for 3 years and had to be encouraged daily to have a teaspoon of thick fluid... but I have probably covered that topic to death! He now drinks and looks after his hydration levels admirably but hates baths and hair washing again. This seems to come in cycles. Inexplicably. Sometimes he loves having a bath, other times he loathes it. And screams and goes mad at the mere mention of it. We are currently in a 'hate' period. He really hates having his hair washed. I casually mentioned that if he had all his hair cut off, then he wouldn't need it washed and brushed as frequently. Later that day he asked for a haircut with "dad's clippers". He was very patient.