I think he has to maintain RO at every interaction with CBSA or IRCC.
It is not that simple: it very much depends on the extend of OP's travel.
@primaprime covers it perfectly, however I believe it is fruitful to bring in real life experience to the conversation:
In the process of going a H&C case myself, I connected with many members in the community who also had went through OR were going through maintaining their PR Status on H&C grounds. I learned that once you receive your PR card, unless you are spending the majority of your time OUTSIDE of Canada, travelling is a non-issue. So for instance, a family friend with a positive H&C case would travel every winter & every summer. They have never faced any issues at the border despite failing to meet their RO. A few other acquaintances have concurred the same - they would get the usual "What's your occupation?" type question, but otherwise, would be allowed through without a word.
From my understanding, the reason for the above is twofold:
- The present officer has access to all the individual's GCMS notes. These notes will indicate that the individual has had a determination made on their status by a senior IRCC official. The above snippet of the legislation I mentioned does not allow an officer to make repeated determinations on an individual's status unless there is suspicion for a change in circumstances.
- If there is a reason for suspicion, my understanding is that the individual will be called into secondary and a ranking officer will investigate the matter further. This point is significantly important since not every officer has the authorization to make a determination on your status. If not officially, the practise seems to be the case de facto, in particular with H&C cases. Therefore, there needs to be sufficient suspicion not only because the law indicates it but also because the time of a ranking officer is being utilized.
Of course, as
@primaprime correctly pointed out, it is not very clear what is encompassed by "grounds for suspicion". However, it wouldn't be crazy to say that the occasional vacation is fine. It would be strange to be sent to secondary because you had a 2-week winter vacation to the Bahamas. Prolonged absences in the order of 6 months+ (i.e enough to be considered non-resident for tax purposes), would likely be suspicious. One would be prudent to ready good reasoning for such a lengthy absence.
And as always, only lawyers can provide the best answer for the above. They not only have inside-out knowledge of the law, but also have significant experience via working with many, many cases on the matter. Unfortunately I am not one (yet), so take my insight with a grain of salt. If within accessibility, I cannot recommend lawyers enough.