The most common and most likely answer to this crossword clue is the 3 plus 3 plus 4 letter word SON AND HEIR
I've seen this crossword clue in The Guardian
S
O
N
A
N
D
H
E
I
R
Buddy explains!
The straight part
We know that "Male who’d benefit/Male who’d benefit" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case male who’d benefit/male who’d benefit = son and heir.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.