Apparently, you allowed him to be your friend on Facebook? You can undo that (block him).
He sounds like a person you rightfully should not want to see again. History with him doesn't give him license to re-enter your life. Just don't respond. If he calls or comes to your door, don't answer. If he has your email address, mark it as spam.
If you want to be kind and reply to the sister, tell her you are not interested in hooking up with this man again, and that you are not the same person that you were in the past, and to tell him to leave you alone. You don't need to answer any questions from her or defend your position. Just say thank you, and hang up.
Since you have made it clear to yourself that you don't want this relationship back, given that you are better off and happier now without him, then stick by it. However, if it was or is not made clear to him of your stand and he sees in you that you can most likely change your mind, you will definitely not be left alone. If you really are decided not to rekindle any relationship or communications with your ex, tell him straight, and not through his sister. But don't meet up, just on the phone and make the talk brief and concise then put down the phone immediately. Should you meet up with him, this sends a signal that there is still a chance. Your call. Choose wisely.
Wow well that's a lot right there Well I am 22 yrs old and I am going to try and let you know what I think. First you sound like you can hold your own and you got GOD on your side you said so you go to church so you shouldn't have any problems with that. Now you never been married you are 29 you said lol just trying to but a smile on your face. First off you want to make sure that what this guy is speaking is true. Just because he got divorce doesn't mean you want to be the rebound of his life. Why weren't you good enough for him then you know and like you said you guys drink drug ect. is he still into that because you don't want that in your life either you know. But first off listen to what you said "As far as I can tell from talking to him, he still acts like it's the 70s. The F word is the only adjective in his vocabulary. I haven't heard from him in three years until the past week he found me on Facebook. I really hate that." WHY WOULD YOU WANT TO PUT THAT IN YOU LIFE. Because he see's that you are doing good or what so I guess I if you want its up to you if you go but just make sure you find out what he wants from you first and are you ready to handle all of this four kids ones that are not yours when if you look at it could of been if things would of worked out in the long run and what does he do for a living you have a good job education you travel you are enjoy in life you go to church is he going to do all of that with you as well (just look at the big picture first I don't want you to step in hot water with out knowing how hot it is) Well good luck if you want to talk you can e-mail me firstname.lastname@example.org
Sure there is a right answer.....You hit on it when you said they should come to you. If he's still on drugs why bother. Everyone does a lot of stupid stuff in their youth and then they grow up and move on. If he's stuck in the 70's...leave him there. If you are curious, invite them to a nearby restaurant for a get together...not just him. He may have finally grown up. Some men it takes a very long time to get it.
Or I might accept the invitation and go visit with his family and catch up. That could be a hoot. You'll get all the info and won't have to wonder. I drive 60 miles to go shopping every so often. That only takes an hour and it gets your car running better. Make a day of it. You won't have to wonder any longer. Any other people you might want to visit? Make plans.
it sounds like you're dreading seeing him again. So don't!