First of all, if your dog appears to be having difficulty chewing kibble then he probably needs a dental exam, cleaning and extractions as needed. Then he will be able to eat any kibble you choose for him.
I would schedule the vet appointment as soon as possible, senior checkup, labs and other testing as recommended by the veterinarian. Dental care for senior pets is very important.
If your dog prefers softer food, you can always presoak the kibble in the fridg overnight prior to serving and it will be soft, the extra moisture is good for him too.
