I think I'm understanding this correctly but want to make absolutely certain before I bring it to the table:
If a PC is grabbed by, in this case, a bear, and he has an ally on the other side of the bear, the two PCs are flanking the bear. In other words, even though the grabbed PC is immobilized, he can still attack the bear and therefore the bear grants combat advantage to both the PC and his ally. Am I reading that correctly?
Thanks.
Best Answer
Yes.
The grabbedDDI condition doesn't prevent you from attacking the grabber, so you can flank it if your ally is in the right position.
As you noticed the only condition that prevents flankingDDI is when either a flanker or the other is unable to attack (e.g.: lack of line-of-effect or impossibility to take actions).