Sorry to hear about your biter
I hope that you can get him through this stage! I have a leather glove that my Bailey, now 1.5 yo, is allowed to 'fight' and bite while I have it on, but when it's off he is no longer allowed to do this. I have done this since he was a puppy and it seems to work. Having said that, he was not an aggressive puppy, just trying his sharp teeth out at the time. Now his favorite toy is the leather glove. When I first put it on I have taught him to sit, then when I say 'fight' he can approach and bite it. He quickly gets bored of this, and wants me to throw it down the hallway. I do this and he races to it and shakes it like it's a rat. I find it amusing as I every time he shakes it, he slaps himself in the head. Silly boy
I hope that you find what it is that will make yours a lover, not a fighter
Just a thought - would the type of food make any difference? Experienced YT'ers here may know the answer to this. Good luck.