I tend to agree. It's not like you're dying tomorrow, but giving those lesions time to develop is not a good idea. He's right in immediately suggesting a biopsy - it's the definitive way to establish if there's cancer there - and the MRI means that when you do get the biopsy done, they can zero in on the exact location of the lesions, to get good samples.

Might be different in your country, but in New Zealand, I was put on a biopsy waiting list in May 2023, as soon as the MRI came back, and had the biopsy in June. But it was an agonising 6 weeks to get the biopsy results that confirmed cancer.

(edited to say that prostate cancer is one of the slowest-growing cancers, so it may not get worse as quickly as you may be imagining. It's the sloth of cancers)