The "huge magnum" is actually a far better idea than a lot of lighter guns. The Charter Pitbull in 380 mentioned in the OP is a mere 20 ounces. While the 380 hardly generates a lot of recoil even in a 20-ounce gun, a 35-ounce K-frame shooting 38 Special will generate even less. Suppose the 380 fires a 90 grain bullet at 1000 fps. The resulting recoil energy is 3.36 ft lbf. at a velocity of 13.14 fps. The K-frame shooting a 125-grain bullet at 1000 fps will result in 3.26 ft lbf. recoil energy at 9.8 fps. Now consider a 44 ounce 586 or Model 27 "Magnum." Even if the 125 grain bullet is fired at 1100 fps, the resulting recoil energy will be a mere 3 ft lbf at 8.4 fps. Unless the person lacks the strength to hold a heavier gun, the recoil will just keep getting less as the gun gets even more "huge."
A steel Mark IV Target is about 43 ounces. The Mark IV Hunter is about 44 ounces and the Mark IV Competition is 45 ounces. These pistols might be too heavy for a little kid whose age is still measured in single-digits, but this is a good weight for a pistol to be used by an adult. For comparison, a loaded M1911 is nearly 46 ounces. Revolvers have the advantage of being able to fire loads with very light charges and not have the action fail to cycle. The disadvantage to them for some shooters is the heavy double-action trigger pull. Single-action is viable for some purposes.
I would also add that the way to get soft-recoiling loads is to use a small amount of a fast-burning powder. Choosing low-pressure loads (45, 38 Special, 44 Special etc.) is not the right way to achieve low recoil. Pressure =/ recoil. Using a lower mass of a faster burning powder will generate less recoil, and it will often cycle autoloaders dependably also.
