If you believe that then you should not ask any friends or relatives to pray for you.
First, I think that you need to understand that Catholics DO believe that Jesus is the only Mediator between us and the Father. That is why all prayers are directed to Jesus Christ, our Lord and Savior, even when we choose to ask Mary and the Saints for intercession. We're not asking them to do an end run around Jesus and go directly to the Father for us -- ignoring the fact that Jesus Christ is the Son of God, and IS God -- we are asking them to pray for us IN JESUS' NAME.
I hope the Scriptures below help:
"‘And as for the dead being raised, have you not read in the book of Moses, in the passage about the bush, how God said to him, "I am the God of Abraham, and the God of Isaac, and the God of Jacob"? He is not God of the dead, but of the living . . .’" (Mark 12:26-27)"Pray at all times in the Spirit with all prayer and supplication. To that end keep alert with all perseverance, making supplication for all the saints, and also for me . . ." (Eph. 6:18).
"Therefore, since we are surrounded by so great a cloud of witnesses, let us also lay aside every weight, and sin which clings so closely . . ." (Heb. 12:1).
"And when he had taken the scroll, the four living creatures and the twenty-four elders fell down before the Lamb, each holding a harp, and with golden bowls full of incense, which are the prayers of the saints . . ." (Rev. 5:8).
God bless.