It's a very worked-over Kestrel, probably a 200-series, can be anywhere from late 80's to 2000, and the photos only support it being a cobbler's pie of parts, tossed together to make a bike. My guess is he had a frame and built it with whatever he had on hand. Mismatched wheels, some odd RD, can't see the drive side to tell what's up with the crankset and FD. Can't tell if he used a threadless headset to use that non-OEM fork, or if he used a quill adapter to make that stem work.
If the frame is in good condition, and that's a threadless headset in good condition (it would be 1" vs. 1.125"), then an offer for the frameset could be $200-$275, but I'd look hard at the seatpost area, bottom bracket area, and the FD and caliper mounts. If they're fine, and it doesn't look abused, a nice platform.
It was definitely not a tri-bike. Kestrel played around with the Ironman brand, not only on that model, but later, on the Talon as well. That 200 series was an excellent road bike, ahead of it's time in some ways, and at that time, probably as good for the Ironman as any (112 miles, you want to be comfortable).
IMO, the frameset is the key, anything else is gravy, tell him to keep that stuff. Toss on a black group, seatpost, and stem, have a killer bike.
Who drummed for Thoreau?
1985 Raleigh Competition (Racing USA Series)
1987 Bridgestone Radac (aluminum) frankenbike
1988 Centurion Dave Scott Ironman Master (steel)
1989 Centurion Carbon-R (carbon)