Hi Delly, I am a bit puzzled as to why the surgeon says your Dad will never swallow. Kris too has had his entire tongue removed. He has been swallowing since he was 3 weeks postoperative. Our Speech Therapist says she can't understand how people like Kris swallow , but they do. There are others on this site who have also had Total Glossectomies and they too swallow. If I was you I would keep asking. Ask why he can't swallow? You don't need a tongue to swallow, though it does make it easier. Ask why he needs to wait 3 months for a swallow study.
Radiation can be rough. Dad is lucky you are there for him. Keep posting here, there are many who will help you both through this next stage.
Tammy

Caregiver/advocate to Husband Kris age 59@ diagnosis
DX Dec '10 SCC BOT T4aN2bM0 HPV+ve.Cisplatin x3 35 IMRT.
PET 6/11 clear.
R) level 2-4 neck dissection 8/1/11 to remove residual node - necrotic with NED
Feb '12 Ca back.. 3/8/12 total glossectomy/laryngectomy/bilat neck dissection/partial pharyngectomy etc. clear margins. All nodes negative for disease. PEG in.
March 2017 - 5 years disease free. Woohoo!