A .22 would be good for plinking, but maybe not enough for home defense.

You should be able to find a used S&W model 64 in .38spec pretty cheap and easy (if nothing else you can order one from J&G Sales for under 300 for a square butt and right at 300 for a round butt Only problem with the J&G guns is that they're bobbed hammer DAO).

Really any S&W J or K frame in .38 would do him well.

If $500 isn't too much (not sure where your bank breaks) there's a nice Colt Agent on Armslist up in Denver (I don't know the seller ... usual disclaimers apply).