From description , it seems either your husband is having plantar wart
. a corn or callosity needs to be pared or excised while a wart can be treated with paring, cryo or cautery. right now as you are not in your home country, just use a corn cap over the lesion. This would scrape off upper layers of skin and might treat these too. infact if a corn or wart is too small, sometimes we just advise corn cap or application of salicylic acid
Hope this helped.