Hi Lea,
So sorry you and your dad have to be on this journey, but I'm glad he has such a supportive daughter by his side. The role of caregiver is one of the hardest, but most rewarding.
My mom was initially told she would be doing the 3 bag method of Cistplatin, in conjunction with 6 weeks of radiation, but before she started treatments they changed it to the 6 bag method. She handled it VERY well, and when I say VERY I mean she almost felt better after her weekly intakes because of the hydration she was getting at the same time. A few days after chemo she would crash a little bit, feeling tired for a few days, but bounced back pretty well before she was due for another. Our perception of chemo vs radiation for cancer treatments is often that chemo is what will cause the most discomfort, but oral cancer is an entirely different ball game. Rads is what will cause the most discomfort, and chemo is the easier of the two, at least when given in smaller doses. I think if it is just as effective, as it seems to be, it makes all the sense in the world to go for the 6 bag method so your dad doesn't have to endure the harsh side effects and can stay strong to fight this.
Best of luck to you both. Please let us know how he gets on.
Amy