IMO, programs are kind of personal, something that has to be researched by the intended user. I wouldn't expect anyone to know what program to buy me unless I specifically told them.
I'm an architecture major, and a good friend wanted to "get me something original" for my birthday (because everyone gets me Disney things... but that's because I like Disney things). Well, he bought me a Home Design software program. It's something that someone who wants to build their own house but doesn't know anything about architecture or construction would probably use. I thanked him profusely, but the program has remained wrapped, sitting in my basement for years. It's just nothing that I have ever had the need or desire to use because I create from scratch and have my own design and rendering programs to do so (actually, it was a little insulting for him to give me an amateur program, but I know his intentions were good).
You've already taken a step to ask the "pros" what they'd recommend. Lightroom or Topaz are good programs, and something he definitely might want to have. But I'd suggest that you'd ask him what he wants because he might have specific needs or wants that we can't address here, not knowing him personally.