Dysphagia Therapy in Myotonic Dystonia

I have a middle aged patient who has suffered with Myotonic Dystonia all of his life. He recently failed a modified barium swallow study and a PEG tube was placed with strict orders for nothing by mouth.

Is traditional dysphagia therapy effective in patients with this diagnosis? Because it is progressive, should he just get used to the idea of depending on the PEG tube from now on?

What is the best plan of care for this gentleman? Information is very limited, even from those SLPs who are my "go-to SLP Gurus."

Thanks!!