Should I get a second cat to keep my current cat company?

You see... I have a cat, about 1 year old, and he recently had a tail injury...before this my mother INSISTED and would physically take him off me to put him outside, luckily now she see's that was a stupid idea and has agreed to him being an indoor only cat... And yeah that's great cause no more risk of explainable injuries from the outside world... but he was a very sociable cat when he was out... particularly him and this male tabby cat (they would curl up on the shed roof together, play with each other, etc) and also my neighbors cat.

Although I am happy he will be inside I feel sad he wont have another cat to play with anymore :/ I mean I play with him but idk...

He is such a lovely and affectionate cat who seems to crave attention from both people and other cats, but then it might be different if a cat comes INTO HIS HOME right?

I don't know what to do for the best, my vet did say he may benefit from having company of another young cat or kitten since he was so sociable but did also mention it may not work out.

What would you guys do in this situation? And if you WOULD get a second cat in this instance, would you get a kitten or a cat around his age?

thank you ~