70% of men aged 70 have prostate cancer, which they will die with, rather than of, it. Many are completely asymptomatic.
There is not really a ‘normal’ PSA range for the over seventies, and none for over eighties.
A PSA of 4.5 wouldn’t really be considered very ‘abnormal’ for a sixty year old, although the increase could be a concern.
I look after two old chaps, one, aged 86 with confirmed cancer he has had for five years, with a PSA of 300 odd originally, and who has hormone therapy, and is doing great, and my father-in-law, also 86, who is crippled with hip pain and who has urinary problems, yet his GP won’t even give him a PSA test, although he’s most likely got PCa too.
Tell your Dad to forego the biopsy, and go for the PSA test in six months. If he is that desperate to confirm that he has cancer, which I said at the start is most likely, he could have a non-invasive bone scan to see if there any signs of metastasis in his pelvis or elsewhere.
Others here will pitch in, I’m sure.
Best of luck.