wet vs dry for kluay

Kluay is 7 year old British shorthair and he refuses to eat anything new. I tried wet food and he eats it for 2 days then stops. So right now we do mostly dry food with 1 pouch in the evening. The vet said the wet food helps with water intake and it is better for kidneys in older cats. I am not sure how much this matters but I give it anyway. Kluay likes the dry food with the smaller pieces, so I check the brand in the pet shop near my apartment in Chang Khlan. Also try to keep the water bowl away from the food bowl, he is very particular.