Kathleen,
Your Mom is making wonderful progress. The speech therapist is absolutely right about her speech getting better the more she talks. I had the same operation done and went back to work in 8 weeks and immediately began making presentations to customers. I know I didn't sound the same, but I went on anyway. Oh, I still complained to anyone who would listen, because in my head I did not sound the same. Even today, I don't think I sound the same, but everyone else says that they can't even tell anymore.
Eating will also get better. I used to tell my husband that by the time I finished eating breakfast, it was time to start on lunch. My tongue felt heavy also, this too will diminish with time. However, it has never gone entirely away for me 2 1/2 years later.
My depression seemed to come and go. I regret that I did not seek help sooner, as it came crashing down on me about a year ago. Depression is normal and for me it was because I was impatient to have things be the same again. I finally came to the realization that things would never again be exaclty the same. This was a very hard adjustment for me.
Your mom sounds like she is making excellent progress and she just needs to be patient. Of course this is coming from someone that wanted my missing teeth back before I left the hospital. My doctors and I still laugh that I still don't have them today.
If you think it would help, please send me your address via private email and I'll write a letter to your Mom.
Thinking of you and your Mom. Take care and be good to yourself also.
Anne.