dunderhi

In my opinion, what makes for a good road time trial bike also makes for a good pursuit bike: aero shapes, low TT, low BB, shallow HT angle, steep ST angle, aero bars, and aero wheels. Aero bars and aero wheels get you 90% of the way there, but pursuiting is such a small part of track racing, the rest of the investment just isn't worth it for most competitors. A serious road time trialist will likely do a couple of dozen time trials over the course of a season, whereas a pursuiter may only do two pursuits all season long: States & Nationals. At these championship events, most trackies break out their disc wheels and the aero bars and they have instant pursuit bikes. Being an old fart with more money than sense, I have a dedicated pursuit bike that ticks off most of the qualities that I have listed above (Argon18 Electron Pro), but I see riders use this same bike with its 72.5 degree HT as a mass start bike in Pro,1,2 track races. So, I do believe most track riders only have/ride one bike for all events.

Overwhelmingly manufacturers don't sell dedicated pursuit bikes either. For example, the Look L96, which is arguably the best commercially available pursuit and/or sprint frame at the world championships every year has the same geometry for both their sprint and TT model, which throws everything I posted out the window.

Here's a frame builder's perspective: Urban Velo #3 - Bicycle Culture on the Skids

Anyway, my recommendation is buy a frame and a set of aero bars that fit him well and spend the real money on the wheels. Which, BTW are two sets: cheapos for training and full-up carbon for racing with lightweight tubular tires. You can hold off on the second set of wheels until you know if pursuiting is still a actually good fit once he transitions in his new environment. I was a national level junior when I joined the Navy and competitive cycling quickly became a distant memory for me.