Thanks for consulting HealthcareMagic.
The clinical presentation of your husband seems to be because of his pants or button ribbing as the other doctors have mentioned. However, as this is occurring frequently and is now bleeding, attention needs to be taken by thorough examination for other possibilities like getting infected secondarily, allergic reaction
to certain fabrics, some other dermatological conditions. I suggest to visit a dermatologist
before it gets complicated as we cannot suggest a particular solution for skin problems without properly visualizing and examining.
Hope I have answered your query. Wish you a good health!