Having listened to the recording, I reckon the guy was unbelievably lucky to get out of that one in one piece. However.....as an area ATCO, and I think a couple of posters have touched on this, I personally would have major concerns about giving flying instruction over the R/T.
Dont get me wrong, it obviously worked out fine in this individual case but society today is one of lightning-quick litigation unfortunately and had this incident had a different outcome, you can bet your behind that the ATCO would have been sued rotten.
It's really a difficult spot for the ATCO to be in as the pilot genuinely sounds like he's gonna crash. Human nature would be to help this guy in any way you can i.e give some a/c handling advice to the pilot but in the process, open youself up to a whole world of crap if it all goes horribly wrong. What lawyer can say if the advice you have given DID or DID NOT result in the a/c crashing??
I'm sorry to say but I would be inclined to let the guy fly (or attempt to fly) the plane and give him all the (legal!!) help I could. Sounds like a cop-out but I would like to know how many controllers out there would actually get involved in giving handling advice, experienced flying instructor or not for fear of legal reprisals????
SD