Well,
given his age you may want to take into consideration that it may be the onset of some form of dementia{due to the alcohol abuse}. But, if he's just an a-hole{and let's face it, we all know them and some of them must have kids}then I would say this{keep in mind, I can be quite blunt}
"Dad, I spoke with {BFF} about hookin' up with you and she said that she'll have to decline your offer, unfortunately the sight of saggy old b@lls skeeve her out, unless they're attached to a big, thick......wallet

.
She added that if she ever has a disfiguring accident you should look her up, as her standards will have probably dropped considerably...but not until then."

I'm pretty sure the subject will never come up again if you say that
