I'll admit up front I don't have much room to speak, but I have flown  IFR in spam cans and fast glass, and it would seem to me that *IF* he could find an instructor that was qualified to teach IFR in the IV, that would be my route.  The scariest thing for me would be for him to go to a field and have some CFI that's been flying around in spammers the whole time to go "Yeah, it's single engine, we can do that...no biggie!" ...and hop in and get a handful if he were to actually take him up in actual.  I was lucky enough to have an instructor who was a former PIC (Prof Inst Courses...not Pilot in Command ;) ) and F4 driver that trained me in pretty much all actual IFR.  Best money I ever spent and never had the urge to "take off the hood" in crappy weather.  I always hear that fallacy of people going back to the "hood" if in actual IFR and they start to get nervous.  If I hadn't trained in actual I certainly would not have wanted to go poking my head in it all alone for the first time because I had been in VFR with a hood the whole time.  People tend to "cheat" with hoods and such anyway (in my opinion...and they are only cheating themselves).
Enough of my ramble and back to the IVP.  All I'm saying is this:  He gets used to being high on the glide slope or a little high on the VOR-A, etc. etc....and you can point the spam can down with some flaps and not break 80 knots... and get back to where you need to be on the approach.  I've never been in a IV but I would imagine it's like my Glasair or worse, and if you stick the nose down a little because of a sloppy approach, you'll be over the numbers at 140KTS and going missed.  I just figured (once again *IF* he can find a qualified instructor in such a plane) that learning in that plane would save ALOT of slop that's going to have to be removed from learning in a spam can.  That is all.

Steve