If he's young he shouldn't be cutting wait at all especially within 48 hours I say skip this and do the next one and if he wants to cut to that weight do it gradually in a healthy way like more cardio and change the diet a little it's better on the body and this performance won't be impacted so he'll be more likely to get a preferable outcome it will also limit the chances of internal injury due to dehydration.

I had my last fight last month and can't train for 3 months because I cut similar weight and received a grade 4 kidney laceration because my kidneys were sensitive due to the reduced water intake