My first breast fed until she was over 2. We were trying for number 2 then and the doctor advised me to stop feeding her as it might affect my fertility. I just stopped. She didn't mind much. As you say, it's not that they need the food by then, it's the comfort, a good cuddle can provide that. Number 2 was 16 months and we had to go away for a few days on business. She stayed with my sister. When we came back she had 1 feed when she woke up, I think just to prove she still could if she wanted to, and then she didn't bother again. Maybe you could try just being unavailable at the times he would feed. Let somebody else comfort him, or give him a bottle instead of the breast. It's the comfort that's important, not the milk. So as long as he gets that he should be fine. Good luck with it and the mammogram. Sorry to hear about your sister.