She may not need a full tongue removal - depending on size and location she may only need a partial. Regardless of this life is okay will either a full or partial. There are people here who've had both. She may have to work on figuring out what works for her in terms of eating but eating and speaking are possible. I think personally it's best for you to be here if you can - older people -especially if they are not familiar with the medical establishment tend to fall into the old mind set of dr know best. Often they do but sometimes they need to be made to look for alternatives - you could advocate for her easier in person rather than trying to push your dad to. good luck!