This is the 4192nd most frequent Arabic word.
فعله
"فعله" means "his action" or "he did it."
In this sentence, 'فعله' means 'he did it' and is used to indicate the action of completing or performing a task specified (the challenge in this context).
قام بالتحدي وفعله بكل شجاعة.
He faced the challenge and did it bravely.
Here, 'فعله' is used in a hypothetical conditional form suggesting what someone must or should do (to strive in this context) to achieve a stated goal.
إذا أراد النجاح في حياته، فعله أن يجتهد.
If he wants success in his life, he must strive.
In this sentence, 'فعله' refers to a specific action performed by someone described earlier in a challenging situation.