Your question is very clear, your brother wants to buy a handgun manufactured by IOF and I am sure he has his reasons for doing so.
The .22 revolver has a whole lot of problems - viewtopic.php?f=12&t=86
Anyways, a .22lr bullet fired from a 3 inch barrel would be comparatively a weaker self defence round than .32 acp.
The choice according to me would be between a .32 revolver or .32 semi-auto pistol. There are a lot of revolver vs. pistol debates on IFG and you can read them up before making up your mind. Please keep in mind the waiting period for purchase of the firearm and resale restriction for five years in case you want to buy it from the factory.