Here is what I would do personally:
1. Buy one of the more "deluxe" equipment setups from one of the sites that @unionrdr linked. You want one with an auto-siphon instead of a racking cane. You can skip the "secondary" carboy (glass or plastic) if you can get a kit cheaper without it (if not though, having an extra fermenter is a good thing, but while it's a debated topic, many of us will tell you that secondary fermentation is unnecessary, and if your dad will only ferment one beer at a time, then the secondary fermenter is useless). If the only kits with an auto-siphon also include the secondary, then buy a lower level kit with neither, and just buy an auto-siphon. That should run you maybe ~$125.
2. Buy a 7-10 gallon brew kettle (the bigger the better). Many brewers start with a smaller kettle, and it's one of the first things they'll grow out of. You can get aluminum kettles for quite cheap. Some grocery stores will have large ones for tamale boils in the latino section. Stainless is better, but substantially more expensive.
3. Buy a propane burner. It'll do the job much better and faster than the stove will.
You can often get #2 and #3 together by buying a turkey fryer setup.
4. Buy a wort chiller. Chilling without one is a huge pain, either requiring a lot of time, work, and ice to get to the right temp, or otherwise causing people to get frustrated and give up and pitch yeast too hot, which then results in flavor detriments to the beer. In either case, more work or less quality product, makes it more likely he won't want to continue. The wort chiller makes everything faster and easier.
If you're smart about it, you should be able to get all for near $400. That won't include an ingredient kit, which can run $40-60 (give or take, some can be less or more than that) for a 5 gallon batch, and will be an expense for every brew (but if he gets a handle on what he's doing that cost can be brought down substantially buy buying ingredients separately in bulk, reusing yeast, and switching to all-grain brewing instead of using extract kits)