This could be some kind of infection, like scabies, but, it is far more important for your father to be checked for Hodgkin's lymphoma and other lymphomas, because they may manifeste with symptoms like nights sweats, fever at night, weight loss, skin itchiness, especially at night, skin rash, cough, feeling fatigue.
Itchiness from scabies is also more prominent during sleep.

He should visit his physician!

hello

I think he has an allergic reaction to something he wears. Synthetic fibers can cause this sort of a problem. Natural fibers like cotton or wool might be the answer
Also soap, or shampoo contains deadly chemicals
Changing brands can often alleviate skin problems. Lots of people are allergic to chlorine and chlorine is even implicated as a causal factor in skin cancer.
The most likely cause would be the synthetic fibers.

Carolin

Hi there

I also think it is an allergy

Kinetico