Should he donate money to a Buddhist temple in order to keep his job and protect himself from any harm?
It is not permissible to donate to a temple or church or any place in which anyone or anything other than Allah is worshipped, because that is helping in evil and in the greatest of evils. Allah says (interpretation of the meaning): “Help you one another in Al‑Birr and At‑Taqwa (virtue, righteousness and piety); but do not help one another in sin and transgression. And fear Allaah. Verily, Allaah is Severe in punishment”
In these temples shirk and idolatry are practised, so how can a Muslim think of donating to them? Can that be anything other than helping and contributing to the support of shirk and those who believe in it?
What you have to do is refuse to give these donations, even if it means that you have to leave your job in this factory, because the believer cannot sell his religion for worldly gain. Work is not one of the things that make this great evil permissible, and the one who gives up something for the sake of Allah, Allah will compensate him with something better than it.
For more information please see the answer to question no. 50173
And Allah knows best.