I have always been a fan of the J-28. The J-28 was part of the first generation J-boat cruising series that included the J-40, J37c, J35c, J34c, and the J-28. These were well thought out, wholesome, and nicely detailed boats. They had very workable ergonmics (except that these never should have been offered with wheel steering. (I would avoid buying one with wheel steering since the design, like most small fin keelers requires a fair amount of steering input and the wheel is not all that well suited to the needs of the boat.) These were not exceptionally high performance boats and really never did all that well as race boats, even at a club level. Otherwise they should be a good boat for your friend.
If you friend is looking for a little more performance, he might also consider a Laser 28. They have a very similar layout down below. I had one of those foe nearly 14 years and it was a great boat for my purposes.