I find Glenn's role puzzling as well. Maybe Urbie didn't tell him everything at the outset, but let it out in bits and pieces, and now Glenn's stuck?
Only a possiblity. But don't think successful and important people can't be bamboozeled. Remember that religious affinity scam in Pennsylvania in the late '90s? The one that sucked in a Rockefeller and Paul Simon, former Secretary of the Treasury? They ended up out a lot of money, and were exceedingly embarrassed into the bargain.
If the O/S is in fact 500B why would a partner at a respected securities law firm take on such a mess?