To put things in context for dead lifts. Ben Glasscock a junior pulled 290.5kg at the South East Astor Winter Divisional contest this year.
At any given power lifting event there will be seniors pulling well over 300Kg, Dave Richardson 340Kg most weekends. Under 59 kg class guys pull over 200Kg. Steven Tyers competes under 66 Kg and pulls 245Kg. So there is room for your lad to improve on for sure.
But let him go for it, nothing beats actual competitive experience.
Strive for continuous improvement, instead of perfection.