I feel for your Dad. As far as hope goes, let him know that even if he never is able to swallow again and is on a permanent feeding tube, life can still be good.
Speech therapy is very helpful - and the SLP can also do swallowing exercises or provide electrical stimulation.
While none of it worked for me, it's a good feeling to know that I tried everything for over a year although it is depressing if it does not work in the end. Go with him to session with a trained speech language pathologist (SLP) who also has training in swallowing disorders so you can get a tentative prognosis of recovery. The important thing for your Dad to realize is that while it may feel like a disaster, it is not the end of the world to lose the ability to swallow. of course, I hope he does bounce back .
keep the faith
Charm