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.
The ownership of the wealth after the death of the owner is transferred to his heirs. The wealth would be distributed among the inheritors after executing the dead person's will. The inheritance would be legally effective only if it was made to those who are not inheritors and provided it does not exceed one third of his whole wealth.
Therefore, you should gather the money of your father, which is with you, with his other money to be distributed among all inheritors according to everyone's legal share. You are not permitted to act in that money freely except when all the other inheritors permit you to do so and their permission is effective if they are mature and wise.
Allah knows best.