Very good questions.
I don't think he can be counted on as an every down LB any more, and unless he played for a really small salary, he wouldn't be worth it to come in as a situational pass rusher. The injuries he has are the kind of wear and tear injuries that can quickly spell the end of a LB's career. Bringing him in would be a risk and, considering the instability of the offensive line (LT position) and depth issues elsewhere (TE, CB), I'd have to pass on Boulware.