CLM is so right!
On average indoor cats live YEARS longer than outdoor ones because outdoor cats gets killed by cars, get into attacks and suffer bite wounds or worse from other wild non vaccinated cats, or meet up with despicable humans that hate cats.
Especially given that the cat is declawed if this were my cat it would never see the outside on its own again. I might let the cat out in a cage on the balcony or i might allow the cat to be out on a leash under my direct supervision but those would be the only exceptions.
here are 2 articles that may help you. Good luck!