He certainly doesn't remind me of Derrick Thomas, but he's one of the best prospects in this draft.
The stenosis is a subjective evaluation that's going to differ from doctor to doctor, team to team. Just as it already has between USC and Georgia. Narrowing of the spinal column is something that's likely going to end your career after 8 years or so, but it's not something that will prevent you from having one. It's not a condition that's going to change in "one hit".
Fact is, the league is already full of players that have spinal stenosis. Some that you hear about, and many more that you don't.
I remember when Chris Samuels supposedly had spinal stenosis.... he had a borderline Hall of Fame career. However, it became an issue towards the end and forced him to retire. Rob Gronkowski was diagnosed as having spinal stenosis. Several players have it. Again, it doesn't prevent a career, but it will likely shorten it.
In other words, it's not something that should prevent you from drafting a player if you have a high grade on him. In my estimation you're more likely to look foolish for letting it be the reason you pass up a player than you'll ever be for drafting him despite it.