Hi there, I realise this thread is over a month old, but I hopefully it's still ok to post here.
My mum is a JW and I was also raised as one, but decided to leave the faith when I was in my mid 20s. I'd say I'm an atheist now.
There are some lovely people in the organisation like any other religion, as well as some really weird or abusive / dodgy ones, but at the end of the day it is a cult, and there is strong emphasis on viewing any information that is not approved by the official Watchtower and Bible Tract Society as something to be ignored or avoided. There's a lot of brainwashing, guilt tripping, 'us-and-them' thinking, and of course obsession with the end of the world.
Covid-19 definitely sets off the 'Armaggeddon' alarm. My mum has mentioned it to me a few times and keeps reminding me to pray and read the Bible etc. I just say ok and don't really do anything. I guess it's her way of trying to show her care and concern, even though she probably realises I'm no longer a JW since I haven't associated with them for years. I haven't told her outright that I'm an atheist, but generally avoid getting into religious discussions with her.
Parents, especially abusive and controlling ones, do have a way of getting into our heads and pushing our buttons.
It is worth enforcing some personal boundaries in your interactions with your dad. If he is regularly abusive then it might be better to avoid all contact. Is there any particular reason to still keep in touch with him?
Have you thought about looking into some counselling or support to help you deal with the pain from your dad being abusive and a poor role model when younger? There is a lot of information online about handling parents who are abusive, insulting or manipulative. Lots of Ex-JWs also talk about their experiences and how they moved on.
It helps to remember that while you didn't have much control over your circumstances as a child, you are definitely in charge of your own life as an adult. Abusive parents will keep doing what they do, but we have the power now to say 'No, I'm not getting into that conversation.' or 'I don't appreciate being talked to like that.' etc. It's can be very difficult to assert ourselves like that, but it's important to remember that you shouldn't have to tolerate nasty comments from anyone, including a parent. He is unlikely to change for the better, so it's easier to change your own approach to him for your own mental well-being.