I would say let him. My dad had a tattoo and was adament about me NOT getting one. He told me that if I really wanted one, to think about it for a year. If I still want it after that year, then go get it.

I did just that. I got the tattoo I always wanted and I love it. But, I also got a spur of the moment tattoo that I HATE! It wasn't thought out and it's impossible to hide.

If he's been thinking about it, then he's ready. But he needs to make sure that the design he wants isn't just a fad or something spur of the moment. Also, he needs to get it done right since, as others have stated, is permanant.

Good luck.