First of I'd like to say thanks to everyone who gave their suggestions and well wishes, unfortunately I didn't get to read everybody's comments as there are too many but thanks to everyone anyway.

Now onto the update. I gave my mother a few days to calm herself down before speaking to her again, she eventually came around. She recognises that it's not optimal for my son to stay with her and that he would be better with my aunt. She knows that my brother is a slob and is giving him a good kick up the arse to get his life together and shit. I have spoken with a lawyer who has helped me with a lot of things including getting my son legally adopted by my aunt and her husband. He will still be staying with me until i... pass As a lot of you suggested I made recordings and videos of myself giving him advice for his milestones. For example: when he looses his first tooth, turning the ages 10, 13, 16, 18, 21, his first girlfriend(or boyfriend if he likes, I've made a video in case he is in any way lgbt ) leaving secondary school, going uni, getting married or if he has any kids. There are also things I've put into writing, like how his mother died and that he was supposed to grow up with a twin brother that also sadly passed. I've also had my lawyer help me set up a little trust to will him £40,000(from my girlfriends father when he died, she put the money in a joint bank account that I got when she passed) in case he needs help with university or decides to go travelling. All I have to do now is to enjoy the time I have left with him, I've moved my younger brother into my flat so that there will be someone to find me everyday for when I go.

When I'm gone I can at least be comforted by the fact that the son I love so much is being taken care of and that I will see the girl I love again and our other angel I never got to meet.

Thank you all again

Edit: this is op's brother writing this edit, he has since died