Im guessing it will be a transperineal biopsy.
This can be done under a local but a general means he will need time to come round from the anaesthetic.
The main after problem can be an infection, but he should be given anti biotics before hand to counter that risk.
There may be some discomfort or pain for a few days after the procedure, but nothing paracetamol won't deal with.
The most alarming thing is blood in his urine, which could last a couple of days, and blood in his semen which takes much longer to clear because it's not getting flushed out. Be prepared for his next few orgasms to be rusty brown with congealed blood. Its scary but perfectly normal.
Be sure to ask how many cores or samples they are going to take. Because there is no MRI to guide them it could be a fair few from multiple areas within the prostate. I only had six taken which is the absolute minimum, I wish they had taken more to give a wider picture.
The biopsy really is no problem at all and he shouldn't worry about it. The wait for results is the hard part. But worrying won't change what the results will be. Just sap his energy for no good.
It could be good news and sometimes thats just as hard to hear if you've got yourself all wound up to deal with having cancer. His emotions will be all over the shop.
Be patient, try not to worry, until there is something to worry about, Mick