you're in Texas, where it is frequently HOT. That means light clothing, which is not good for concealed carry.
The 4" is just as easy to conceal as the 2", really, and is a little easier to shoot well. The hogue or Pachmayer grips on a wheelgun don't help in concealment. That being said, I think your brother needs something he can hide better.
If he insists on a full power gun, he shold look into one of the Glock autos. They make a good concealed carry piece. Also look at the DAO (double action only) autos from smith and wesson, taurus, Kahr, or one of the other reputable makers.
Personally, I carry a beretta .32 auto, for one reason only--it is easy to hide, and I can take it anywhere I can wear clothes. The first rule of a gunfight is:
Have a gun.