Urinary tract infections and sepsis are potential consequences of any prostate biopsy, but are more likely with a TRUS (up the bum) biopsy than with a trans-perineal procedure. The incidence of complications is however in the low single-digit percentile.
He will get anti-biotics after the biopsy and that should limit the risk of infection.
Go for the biopsy next week and enjoy Mexico. I am there in two weeks, so keeping an eye on the National Hurricane Center website!
Best of luck for a good result, and enjoy your hols.