Get the healthiest wet food you can get. It may be a little costly, but what's more important? I think that's your animals health, and if he/she is alive or not. So get healthy wet food.
You will want to purchase the healthiest food because a lot of wet food has some "unhealthy" ingredients. So getting the cheap stuff would be bad for his tummy, and may be worse because the cat is elderly.
- Bad teeth is a common complaint in elderly cats and there is almost no way of completely preventing it, as most old cats will experience teeth problems sometime in their life times.
- It has been suggested that feeding cats more hard food when they are young adults could have benefits for their longer-term dental health. It is thought that hard food doesn't let plaque build up on the teeth as wet foods do.
- However, if your cat already has bad teeth - as is the case here - then feeding it hard food is not a good idea.