I had the guys soak their feet in epsom salts, dry them thoroughly and then use Dr Scholls foot spray for athletes foot, and then clean socks. Respray and change socks in the morning and afternoon too. Once it was under control, they only had to use the spray in the mornings.
I bleached their socks to help kill the fungus too.
We also got boot dryers, used them for their shoes every night. When the weather was nice, I set their shoes out in the sun to air and dry them out too. Loosen up the laces and open them up as much as possible. :D:D:D