As the medication was prescribed for your use, even though it is an antibacterial cream, it is not a good idea to send that to your boyfriend.
He really should see his own doctor. The problem he has may not be bacterial, but a fungal problem and that would be treated by a different cream/ointment.
Encourage him to see his medic.
If he can get hold of some natural set yogurt (plain), that will help if his problem is caused by fungus. The yogurt helps to cool the skin and ease any irritation and also acts as an anti-inflammatory.
he may have picked up something different completely from the toilet seat, so it is a good idea to get checked out.
Before sitting on a toilet seat, tell him to wipe it with a toilet tissue, or put some toilet tissue on the seat before sitting on it.
Best wishes.
The government does not allow the mailing of ANY medication to troops anywhere. I know this because I offered to send my son tylenol for headaches, and was told immediately that I am not permitted to do even this simple thing. Your fiance must see his medical officer for treatment. Blessings - Blu PS: tell him that we appreciate his service! :-)