Dog with Megaesophagus?

[sunnys best friend]

With regard to the chair, he needs to get used to it. If you feed him every time he goes in it he will form an unpleasant association and pretty soon you won't get him in it at all. So pop him in at random times and make a big fuss of him, and play with him.
The feeding is harder - do you use a syringe? Again getting him used to it, maybe smear some meat paste round the end and let him lick it off. Don't always show him the syringe with the chair, too - again the association. Make it all a huge game, praise him up and never shout at him. Away from mealtimes play with him a lot - this helps him to bond with you and trust you, plus he will become hungry and more receptive to the idea of eating. Good luck!