The most common and most likely answer to this crossword clue is the 2 plus 2 plus 3 plus 6 letter word GO TO ANY LENGTH
I've seen this crossword clue in The Daily Telegraph
G
O
T
O
A
N
Y
L
E
N
G
T
H
Buddy explains!
The straight part
We know that "to do everything possible" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case to do everything possible = go to any length.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.