If his status expired more than 90 days ago, there's no way for him to be in status now, unless he leaves and is successful re-entering Canada.
He will not be eligible for an Open Work Permit until he reaches stage 1 (AIP) which is currently ~ 16 months after CIC receives the Inland application.
Without status, there's no guarantee that he will not be removed from Canada, but having an Inland application submitted may help. However, if he's already on CBSA's radar and is, in essence, removal ready now...the Inland application will not offer much protection.
Without knowing more about his situation (see scylla's questions), it's hard to offer anything more.