Flat Spot,Nail in tire. Been driving with it. Slowly leaking. Left to park for now. Is the tire unrepairable to a point?

Had a nail in the front tire for some time. I've left it to park for now. When I came back two months later the tire pressure was at 99… is there a point when the tire is dead, or can I simply patch it even though so much time went by?…

My car has 66000 miles.
My car has an automatic transmission.