For maintainint RO for PR, someone can be outside of Canada for up to three out of every five rolling years.Leaving country for a short period (for vacations, meeting friends and family, or going back to country of origin for few months) is not prohibited. Permanent resident need to be in Canada for a minimum of 730 days to retain their PR status. If you visit your country of origin after 2 years and spend their 4 months (to spend time with your newly wedded partner) does not makes someone ineligible to claim additional points. My brother owns a business in Canada and soon will apply for citizenship (he has no intention to remain outside of Canada).
However the same rules don't apply for claiming the 15 points for having a sibling living in Canada. For claiming the 15 points, it's not about whether your sibling meets RO but about whether they are in fact living in Canada primarily when the application is submitted and while the application is being processed. There's some possibility IRCC is questining whether you can claim the points if your brother was outside of Canada at the time you submitted your application and remains outside of Canada until today - they may be wondering if he living outside of Canada at this time. As said earlier, I think the most you can do is wait until he is back in Canada and then submit additional evidence of his residency in Canada. The timing of his 4+ month trip outside of Canada is a bit unfortunate given the timing of your PR application. But appreciate you cannot control that. Good luck.