What is the painful rash on hubby's 'member'?

Don't know... ...Without a description of what it looks like, or direct observation. If it's a group of painful blisters on a red base, it's probably herpes simplex. It could be a superficial skin infection (impetigo), or a simple rub reaction due to friction. It could be other things as well. You really should let a dermatologist examine him directly.