I NEED to ween this kid!

My son is 2 and he still breast feeds at bed/nap time and I'm just so drained and ready for it to be over! How can I start weening him? He absolutely refuses to sleep with out my boob in his face 😭. Once when I had to take my daughter (7) to the emergency room my mother was able to get my son to sleep since we didn't make it home till way after bed time but I can not ask her to stay for a week and help ween him.. My SO can't help because he works nights... Any tips and advice would be sooo helpful!