Mary's meaning

My oldest son developed a serious, though non-lie-threatening, medical condition, and the role Mary plays for Christians became clear. She had to watch her son suffer, and she models for us what a true Christian is to do: trust in God. She was able to be this model only because, by God's grace, she was sinless. She didn't confuse herself with the "if only" thoughts that plague the rest of us.

What does this have to do with the "Real Presence"? The thought came to me while praying (for my son) in front of the Eucharist.