That dry food addiction is a tough one, but can be overcome. I would get some high quality canned food and start with putting just a teaspoon in with his dry food. When he starts eating that because of all the dry food around, little by little, put more wet food in, less dry until he is eating the wet food.
Once you get to that point where it’s mostly wet, you can throw some of the dry food on it to get him started, and once you get past that, what we’ve done is to get an inexpensive coffee grinder to grind up their dry food into a powder. You can then sprinkle the powdered dry food onto the wet food to get him going. Even if he eats down past it and stops, you can just add a little more.
The reason this works so well is that there is a coating on dry food that, in and of itself, has an addictive quality that makes cats keep wanting to come back. So the smell of this stuff should help to get him to eat his wet food.
You may have to try a few different brands of wet food to see what he likes, but you might look into Wuruva, Daves, Stella & Chewy’s, Pure Vida, & First Mate. Texture is big to cats so if he likes shredded, he might like Wuruva. Other brands have gravy dishes, or paté or whatever.
The most important thing is not to get discouraged. You can do this and it will be better for your cat’s health in the long run.
Hope this helps. 🙂