I am basically certain that one of my male family members earn their money illegally. Another male family member gave the one who earns illegally a loan of around 105 pounds. Later the one who earns illegally gave it back but gave it back in cash and that cash I am certain was earned illegally. Now it was given to me as an amanah to keep safe for the family member who loaned the money. The family member who loaned the money is my father. Is it halal for me to give him this money that I know the other family member has earned unlawfully. My father wants to spend the money on me, is he allowed to do so. If none of these options are available, what can I tell my father, I am surely not allowed to withhold this money from him and also it is impossible for the family member who earned this money unlawfully to be able to return it.

You are not obligated to withhold this money or give it back, since the sin of earning it illegally is on the person who earned it. Your father can take it and spend it on you.

Yes, an exception would be if that specific money was stolen. If it’s stolen money then you would not be able to take it and you should tell your father about it so he can return it and get proper money from him.