David:
A speech therapist would be the best person to ask. I'm sure your team has one available to consult.

My dentist game me some exercises.
(1) Push tongue out to left, then right side, hold for 7 seconds each; (2) Push tongue out, then up for 7 sec. and then down 7 seconds.

Neck: Turn neck to left side, hold 7 sec. then do right side.

Mouth: Open like your yawning or eating an apple, hold for 7 sec. Push lips out like kissing, hold for 7 sec.

These may help, but please consult with your doctors
Sandyst