She needs to know you're not comfortable being in the same room as this dog. After neutering, he needs to learn some basic manners or she will end up with no friends and possibly with some doctor bills.

I am babysitting a 5 year old dog that hasn't been taught manners either. She is not mean, but still needs to learn not to jump on people and some other basic things. It make her unpleasant to be around. Her owner is too indulgent. Sounds like the same scenario.