It isn't an issue of "need." That's why I said to go with .357 brass if he already had it.
I was just pointing out an additional option that nobody had mentioned. In my area, it's not impossible to get .38 Special brass for cheap or even free (just pick through the brass bin at the range). If dad only wants plinking rounds, .38 Special rounds will get him there. And, you are correct--light .357 Mag loads will do him just as well. There are just more slow/poopy .38 Special loads available to choose from. The OP originally was talking about powder choices, and he'll get more powders to pick from with .38 loads that will keep him at the desired speeds.
