The most common and most likely answer to this crossword clue is the 12 letter word CROWN-PRINCE
C
R
O
W
N
-
P
R
I
N
C
E
Buddy explains!
The straight part
We know that "Perhaps Charles" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case perhaps charles = crown-prince.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.