Off feed help. Going on 5 months now.

[Eceukool]

Hey everyone, new to this forum because I just dont know what to do anymore.
On November 16 2016 I received a male ball python birth year 2013. Since he has been with me he hasn't eaten once. He just doesn't show any signs that he is even a bit interested... I know it's normal for bp to go on a hunger strike but i never had one go for this long. He has lost 167 grams. He is in a 1.20 meter long vivarium. Warm side is at 89C° and cool side is at 78C° I have tried everything I can think of. Mice, rats all different sizes. I have tried assist feeding and just a few minutes ago I have tried force feeding a pinkie rat. Managed to get in all the way in. All you could see was the tail but he spat it right back out. I just don't know what to do anymore. I am really worried which is probably silly of me. Does anyone have any advice? Is 176 grams for 5 months loss still ok? Could it have something to do with breeding season? He was used as a breeder from the last owner. Sadly I can't contact that breeder because she also sold me a bp that has an underdeveloped jaw without telling me that and we left off on a bad note. (Which that snake is doing wonderful. But also took me 3 months to get her to eat) any advice is very much welcomed!

Sincerely, Eceukool