If what he really wants was for the one tooth to be reshaped to look exactly like the other tooth then veneers don't really do this, do they? At least not a single veneer. Both teeth would need veneers, and then they would look like each other but not look like the original teeth. Or can they make a veneer for one single tooth that would make it look like the other teeth without making it look out of place or without creating a veneer for the "good" tooth to match them up? When my wife had veneers done they told us it usually needed to be an all or nothing kind of thing, at least on surrounding teeth, as they can look out of place and it is very difficult to do a veneer on just one or two teeth and make it look natural, and can raise the cost. She had issues with 2 teeth from when she was a kid and we had them done on those 2 teeth. For the most part it worked out ok, but you can tell if you look at them for more than a couple of seconds. For the most part you wouldn't notice, but she notices every day in the mirror and it gets on her nerves. We will likely have the surrounding teeth done at some point to even it out.
This is where it get tough. It depends on a lot of things. Thickness of the tooth, translucency, shape, size, age of the pt, color, more boring stuff.
We can do one veneer at a time and make it look amazing. BUT, it takes work. We take shades under different lights, we do wax-ups, we take molds, molds and more molds. We involve the artists from day one (lab techs) and go over pros and cons of what is possible. Sometimes we can't do just one, and when that happens, we go over why.
The problem most of the time is the depth of the dentin and shade matching. Most docs aren't willing to do the work, for millions of reasons. There is nothing wrong with it. It is much easier to match six man made veneers than to match one veneer with five other stained, imperfect teeth.
So, can it be done? Absolutely. My dad has just one that we did last year. You can't tell which tooth it is.
The funny thing is, the biggest hurdle I've had to doing just one is the patient themselves. It's funny. When they go to one dentist, and he tells them they need six veneers at $900 a pop, then they come to see me, and I tell them with the extra work we will go through to do just one, it will cost them $1200, the decide they like the $900 option, which ends up costing them $5400 vs $1200. The psychology of it all is very interesting.