If he's not used to chewy things it may take a bit for him to accept them as food. I had one cat that dove into a whole chicken wing with joyous fierce growls while his brother looked at me piteously and wouldn't even try to eat until I gave him chicken cut up in little bites.

Dry food is full of so much crap, some of it not even food. I agree the canned mush can't be good for their teeth and jaws.