You can definitely find a decent tripod in the $100 price range. It's not likely he needs the superior weight ability of the super-heavy duty carbon-fiber and pro models, or any serious specialty heads at this point such as gimbals or Wimberleys. The el-cheapo $30-50 tripods will actually do OK too, but they tend not to last as long - I find the $100-150 tripods a nice middle ground. Smaller and light enough for most jobs, upgradeable (changeable heads) for future needs, and more durable and long-lasting than the cheapies.
I've had very good experience with a Slik Sprint Pro EZ tripod, that I use heavily for the past 3 years for night long-exposure shooting, which has also served some double duty for wildlife shooting on my 300mm F4 lens or 200mm-500mm lens when birding. I tend to do much of my wildlife shooting handheld, but sometimes the tripod can come in handy especially if I'm bringing two camera bodies because I can mount one on the tripod and hold the other, making switching between them a breeze. Velbon is another brand that I've had past experience with and heard good things about, in that middle price range.