I’m so sorry to hear about the loss of your Dad. It seems like he was the rock for you and your sisters. Sounds like you have talked about and shared a lot of experiences together. I can’t begin to imagine how painful it must be to meet as a family when your Dad has left a gaping hole in your life.
It’s natural I think to feel lonely and miss Dad especially when you are isolating right now with Covid. But it also seems that you are a very strong person having come out of difficult relationship when you were young. It’s clear that your loving nature is your strength and that keeps your family together.
Perhaps you can continue the bonds you shared with Dad by writing letters to share what your little son is doing and his milestones.
It is also so important to look after yourself during these difficult times. Please treat yourself with kindness.
I hope you have someone to support you and talk to. You could call the helpline at Griefline on 1300845745 6am to 12 midnight to chat to a friendly volunteer about your feelings. There are also some excellent coping strategies in our article ‘Coping With Grief’ here: https://griefline.org.au/resources/understanding-the-symptoms-of-grief/
Continue to keep in touch through this online forum and look after your self. We are here listening to you.