Like I said it sounds like this is largely irrelevant now. If what needs to happen is for him to return to get necessary documentation to reapply, you'll need to make that decision. If you're concerned about travel while an application is in progress you should consider reapplying outland when you have the documentation that you need (no work permit option available with the outland stream).
I'm not sure exactly what steps you took - if you applied for spousal sponsorship inland with the OWP, there was nothing preventing him from leaving.
Your concern likely comes from the fact that CBSA reserves the right to deny him re-entry and if this was the case, the application would be abandoned. That said, inland applicants take short trips and face no issues returning to Canada pending they meet admissibility requirements.
