Cut all contact with my abusive Father seven years ago (had been low contact nine years prior). Most of his family live in another country and his Mother called me when I was 15 to say I was dead to her (for not immediately answering an email) and hasn't spoken to me since. It honestly doesn't bother me as they're all very abusive and dysfunctional. I have no idea who's alive or dead and never think about them.
My Father does attempt to stalk me and his ex wives, especially online, but he lives in the US last I know so am not particularly concerned, just don't like being reminded of him as it causes flashbacks and nightmares. I never think about him otherwise or wonder what he's doing, I'm just grateful for the peace. When my Daughter's born mine and my partner's family have all agreed to say he died a very long time ago and not say anything about who he was if she asks any questions. We don't want to pass down trauma to her.
My advice to anyone considering going no contact with a relative is to do what is in your best interest regarding mental, emotional and physical well-being. You may encounter some well meaning relatives who try to guilt trip you into reinstating contact, but please ignore them and do not allow yourself to go down the "what if" road. I was guilt tripped by my Grandma who said if he died I could end up regretting it for the rest of my life. I re-established low contact age 16 and all it did was expose me to more abuse. She did apologise as only meant well, but it did cause years of psychological harm.
If you are going to go no contact, do not tell that person of your intentions beforehand as it will give them a chance to scheme or manipulate. Cut all contact with a single message (email or letter with proof of receipt) when it is done outlining they are not to contact you ever again (be explicit, such as not over the internet or through relatives and third parties).
Once you go no contact stick to it and do not engage if they try to contact you. Even non-verbal action is a form of communication, do not give them anything to feed off of. Make it clear to others that they are not to tell that person anything about you. If you suspect some relatives or other people are feeding them information, tell those people separate things and see what gets back to them as a way to weed out anyone betraying your trust.
Best wishes. x