Is the money earned by my father from private tutoring female students unlawful, and is it permissible to donate his money if its source is doubtful?

We have previously discussed the regulations concerning private lessons and a man teaching female students. If these regulations are met, then there is no harm upon your father. Otherwise, he would be sinful for the religious transgressions. However, this does not necessitate that what he earns is unlawful, because his earning is in exchange for work that is in itself permissible. There is no harm upon you in benefiting from or giving in charity what your father has given you of money, even if you do not know whether it is lawful or unlawful, because the default assumption for it is permissibility.