Good grief was this totally inappropriate?

Personally I can’t believe you need to even ask anyone else.
You know the answer really.

Sadly I don’t see how you can recover the relationship.

Move on.

It might be a sign of dementia. I find some men get cruder in the way they speak as they get older. We have an elderly workman who visits annually a couple of years ago I was on my own and I realised he had me doing jobs for him like putting protective paper down. He was what my DDs would call an upskirter. He had dementia.
Do you have any mutual friends you could ask to see if they have noticed a change in his behaviour or language?
Personally, I would block all calls and if he persists, threaten to go to the police this constitutes a nuisance call.

If he did apologise and you continued the friendship, would you feel totally comfortable with this person, or would there be something in the back of your mind waiting for another occurrence?
Likewise, knowing this is in his mind... could you remain happy and contented with his company?
Personally, I'd be thanking him for his past friendship but telling him in no uncertain terms not to contact me again.

Has he been in touch since to apologise? Completely inappropriate. You can send a final message if you feel you should but if he hasn't even had the good manners to say sorry, I would block him and delete his number

Totally inappropriate regardless of cause.
Just for information - Inappropriate sexual behaviour can be an early sign of Frontotemporal dementia/Pick's disease. Maybe bear this in mind when considering the cause.

No you are not being prudish! This was totally out of order and would seem out of character for him too. You already have experience of a partner with alcoholism, please don't step out of the frying pan into the fire! A massive dilemma indeed, and I am in no position to advised really, however I urge you to be very careful indeed! Do you have any close you can confide in?

Run.

There are men around who arent abusive idiots.

You could see if he apologises quickly and see how you feel then. Would you forgive him if it was the drink talking or would that make it worse.

delete
block
and move on.