Unless this dude has HIV already it's a risk to himself also. So pretty dumb all around.
I assume that, if he doesn't havs HIV, his reasoning is that he is already over 70 so that if he gets the disease its probably easy to keep it under control with medication for the rest of his life.It's actually dangerous for him even if he already has HIV. If you get infected with a different strain of the virus it can progress faster or even become immune to some HIV medications used nowadays.
If he doesn't have a disease it wouldn't really be actual "punishment" for the girls giving him an attitude, except for scaring the shit out of them. At least they cant get pregnant through that way, haha.
But yeah, i hope he doesn't have a disease and i hope he doesn't get one because he would pass it on.