If you already have .357 brass, just follow the suggestions you've been given.
But, if dad just wants to plink, you can get used .38 Special brass for next to nothing, and you can choose from a plethora of soft loads at:
http://www.hodgdonreloading.com/data/pistol .
As for powder, I have had good luck with 231 and Clays for softer loads.
Good luck!
