Macon Ga Roofing issue.

[D'Antoine Hills]

Just purchased my second home in Macon 31204 and the ceiling in a few rooms were molded. I took the drywall down from the ceiling and noticed the plumbing vents weren’t covered properly because I could see outside the house from the inside. In some places the roof is leaking where there is no plumbing venting. The roof had been replaced in 2013. Should I replace the entire roof or is repairing what’s there an option?