About the only comparable models to the S&W are Rugers and the older Colts. The old Charter Arms Bulldog in .44 Special is an excellent piece also.
If you intend to carry it in your pocket, unholstered, the shrouded hammer is a good idea. Otherwise it makes little difference, as SA vs. DA firing within a snubbies effective range is about the same, accuracy-wise. Cocking a shrouded-hammer pistol is clumsy and, with some older models, hazardous (if the firing pin is on the hammer, your thumb slipping could cause an accidental discharge).
The .38 S&W round is an antique with little power, continued in production only because of cheap imported revolvers that will only chamber it. The .38 SPL round should be easy to find, as many people still use police and military surplus revolvers.
I personally wouldn’t carry a small revolver for personal protection. There are so many excellent subcompact 9mm (and larger) semi-autos available; better stopping power and faster reloads.
The .38 SPL round is about the bare minimum power level for self defense. My wife only carried a .380 Walther PPKS because it was the most powerful round she could control rapid-fire with such a short barrel (she weighed less than 100 lbs), Cor-bon ammo made up for some of the .380s weakness. She was also trained to fire 3 round strings and aim for the head (7 yd range and less).
.45 ACP ammo should be easy to find anywhere. Has your BIL been looking in gun shops or just the Wal Mart?