What is his current status does he have an SP or WP and if applicable an entry visa that is valid for more than 6 months? If yes he can travel and return.
When you say submitted, did you mean uploaded in GC Key, I hope you/he knows that PCC is one of the mandatory documents. Without a PCC the application if submitted will most probably be rejected, some have been successful by initially submitting proof of applying for a PCC but it is no guarantee application will be accepted. With today's scrutiny and issues with temp residents, I feel it will be a sure-shot rejection. I hope he has not filed the application without PCC yet.
Also, the BOWP can only be applied after AOR is received, and in his case, if he has filed for PR without a PCC, both PR application and BOWP might get rejected. His travel to India might end up in a nightmare.
Sorry, I wish I could give better news, but he seems to have failed to anticipate and not apply for PCC ahead of time, if he is in Canada, knowing well that Indian PCC is taking very long.