Momsays, sorry, didn't get back here for a few days. Just a busy time of year!
We live in Alberta where the prairie sun & breezes/winds are very nice for laundry.
I have allergies & DH asthma so we too are careful about what is used on laundry.
You might experiment putting a little plain mineral oil in your son's bathwater to help the itchies.
It's really a must for me & I wash my hair separate also since shampoo causes dry skin. Like someone else said, fragrance is best avoided.