Husband Just Experienced These Symptoms While I Was Changing A

Husband just experienced these symptoms while I was changing a bandage on a serious wound: sweating profusely, weak, grey/ashen color, lost control and wet himself, and ultimately fainted. This is a wound that is 10 days old, has been on antibiotics since, and taking his normal meds for high blood pressure and cholesterol.
Any ideas why this would happen? No history of those symptoms previously.