Saints and Mary help us as models and intercessors. They teach us how to pray and discern God's will. They also go with us to Jesus supporting us in our faith and worries. Then it is up to Jesus to do the rest. It was his intention to make of his followers a Communion of Saints, meaning a community of interdependent believers helping each other in the name of Jesus.
Nobody is an island, isolated from everybody else.
The saints are not dead but alive and well with God. Thanks to their spiritual intimacy with God they have his ear. He is the master, the sole mediator. He entrusts her to John, and the apostle John to her motherly care. Being disciples of Christ ourselves, we have mutually inherited new hearts.