Can a daughter pray and make up the prayers of her father who does not pray and is in a coma with brain death? And what can be done to alleviate his suffering?

A person in a coma is not obligated to pray, nor is he required to make up any missed prayers. Prayer is a physical act of worship that cannot be performed by proxy, except for supererogatory prayers (nawafil), the reward of which his daughter can dedicate to him. He should be prayed for, for healing, and for acceptance of God's decree and destiny, as affliction may expiate sins or raise one's status. Relatives cannot alleviate his pain, but they can pray for him and be gentle with him as long as he is alive. If he dies, they should pray for him, seek forgiveness for him, and give charity on his behalf, as charity reaches the deceased. There is no evidence that a pregnant woman's prayer is equivalent to seventy prayers.