Is it incumbent upon friends who became aware that their colleague spent ill-gotten money, which he took from his father, on them, to dispose of this money? And if they dispose of it, should they give it to his father if he is alive, or should they give it away in charity on his behalf, especially since searching for him might be difficult?

What the son takes from his father's money without his knowledge and consent is not permissible, and it is not permissible for others to deal with him in it. The one who takes from a usurper, a thief, or an aggressor, their ruling is the same as theirs, if they are aware of the transgression against the rights of others. Therefore, if you have taken from this money, you must guarantee it and return it to its owner if possible, and if that is not possible, then donate it as charity on his behalf.