The PLO (now the PA) turned Lebanon into a battleground during their stay there, before the Israelis evicted them in the 80's. I expect this is more empty talk from the PA.
The PLO/PA doesn’t want any more competition than it already has (HAMAS, et al) If their Hezbollah cousins get kicked out of Lebanon, they will move in with HAMAS. So the logical thing is to cooperate with Lebanon and hope they exterminate the leadership there, so they won’t have to do it in GAZA..........