My cat is sad after tooth extraction. How to keep him happy indoors?

Poor Cezare! It's no fun to be recovering from surgery, but it sounds like you're doing a great job protecting him.

One thought is that if he's only inside because of the neighbor's kibble, you could ask them to bring the kibble in for the remainder of his recovery period. If he's inside for the other reasons as well (such as still needing regular medication or rest), walks outside on a harness or just hanging outside with him on a long lead and the harness can give him an outlet.

I'm not sure if you'd want to spend a bunch of money for just the next few days, but if he likes to hunt birds outside, there are bird feeders that can be attached to the outside of your windows to attract birds and then have a one way glass so Cezare could see out at them. If he likes to hunt mice, Doc and Pheobe's makes a great indoor hunting toy: https://docandphoebe.com/ You could use some canned food in this.

Finally, if he's really struggling, I would recommend asking if you can come in for a check up 7-10 days after the dental surgery to have the vet evaluate Cezare's extraction sites and see if they are healed enough to resume eating hard food before the full 14 days is up. Some animals take the full 14 days, and others are ready to go sooner, so it might be worth an exam fee to check.

Wishing you the best of luck! I hope Cezare is back to his normal self soon. Thanks for using PetCoach