Sadly this story isn't uncommon. I'm thinking you are younger and he is too this being the case this cancer can be very aggressive, and yes they will do what they have to to help him. Unfortunately being passed around and misdiagnosed wastes a crapload of time and allows the cancer to spread. Usually if it is a young person only an experienced ENT (who very is familiar with oral cancer) would know to check for it. It's not common in the young though we are seeing a lot more of it these days.

Disfigurement is a possibility. But a good plastics guy, and talented surgeon can minimize the damage depending on how extensive the cancer is. He will have scars but if the jaw replacement (I am assuming they are doing one) goes well he will look close to normal. If his body rejects the grafts or the cancer is persistent then it up there could be some issues with disfigurement but that's a hurdle you'll cross when the time comes. At this point survival is primary.

A feeding tube is nothing. If all goes well after surgery and treatment - he should be able to have it removed - dental implants in his new jaw are a possibility down the line and speech should return.

Some of our members have their whole tongues removed and can talk and taste.
Some have had half jaws and whole jaws. An some - years after treatment are still improving.

Hopefully he will be a best case scenario - hugs and blessings to you.