Well, I think the advisability of investing all his IRA in any one investment is dubious, particularly if it would represent the overwhelming majority of his investment portfolio.
However, we don't really know that.
If, for example, it would amount to a 20% investment of his total portfolio, and he ladder's it in(some now, and some latter(lower or higher)), and he can afford to make a long term investment(won't need to draw on significant cash in the near future),
then I'd have no problem with the idea-
particularly since I have considerably more of my portfolio % in Ariad.
I think you may be evaluating this proposition totally from the perspective of a poor graduate student-
From that perspective, it would, of course, probably
be a little too risky.