What is the ruling of Islamic law on reporting a colleague who has been falsifying fingerprint attendance and departure times for more than a year, given the fear of advising him or him facing problems due to the report?

What your colleague is doing is forbidden (haram). It is not permissible for you to remain silent about evil, cheating, and betrayal, unless you fear harm. You must advise him and forbid him [from doing it]. If he does not stop, inform whoever can prevent him from committing the evil.