I don't know where you are located but if you are anywhere near a Bravissimo it would be worth visiting them, the fitters are very good and there is always a seating area with a variety of magazines for partners/friends.
Alternatively if you are in London try Rigby and Peller, they do fittings for women who have had mastectomies so I would guess they may be able to help with other medical related issues. The first time I went there it was fairly quiet and half way through my fitting it was suggested that I should go and show Vernon (who was sat in the waiting area with a copy of The Lady) the bra I was trying at the time, so male partners definitely welcome!