All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
First of all, we ask Allah to have mercy upon your father, and to grant you patience.
The research that you mentioned does not result in anything, so you should not preoccupy yourself with it. Rather, preoccupy yourself with supplicating for your father and seeking forgiveness for him, giving charity on his behalf, and maintaining ties of kinship with relatives and his friends, and other aspects of being kind and dutiful to your father after his death.
Allah knows best.