The most common and most likely answer to this crossword clue is the 6 letter word SHAVER
I've seen this crossword clue in The Guardian
S
H
A
V
E
R
Buddy explains!

The straight part
We know that "Young lad/He’ll not need this" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case young lad/he’ll not need this = shaver.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SHAVER mean?
SHAVER noun- One who shaves.
- A barber, one whose occupation is to shave.
- A tool or machine for shaving; an electric razor.
- An extortionate bargainer; a sharper.
- One who fleeces; a pillager; a plunderer.
- A boy; a lad; a little fellow.