This is a problem with my side of the family, I had it, my youngest daughter has it too... Couple things... First, get your bf to buy another pair of shoes/sneakers.. And switch them every day, gives the other pair a chance to dry/air out. Second, baking soda, helps dry/kill the fungus that's in the shoes. Lysol once a week or so also. Dr. Scholls Oder Eaters work well. Dye in the socks can cause it too.. I had to switch to just plain white socks to curb feet sweating.