He is claiming if a human lives their entire life without sin, they wouldn’t need Jesus to die for their sins.
How is that false? You say original sin didn't count with Mary. Okay, take original sin out and tell me why a person who didn't sin even once their entire life needs Jesus' sacrifice.
Wouldn’t that mean that fetuses killed by abortion and miscarriage are sinless, also perhaps young babies that die?
This is not the case though, there is such a thing as generational sin and God punishes descendants for their parents’ sins, this is throughout the Bible.
Yes indeed, and Mary was born into humanity, complete with the curse of original sin. You claim God punishes descendants for their parents' sin, yet claim God just chose to spare Mary that punishment? I don't buy that.
But Mary was spared this Original Sin. She did not have the curse of Adam and Eve on her. She was the “New Eve” just as Jesus was the “new Adam” and they did not fail like the original Adam and Eve did by giving into temptation and sin.
That's your argument but you fail to follow through on the ramifications. First, there is no support for this idea in Scripture. It's just not in there, which leads you to insist cherry-picked non-Scripture has the same authority that Scripture does, and that's not acceptable. Second, as I have repeatedly said, if Mary had no original sin, AND she did not sin her entire life, tell me why she could not walk directly into God's presence without a redeemer and not be instantly destroyed. She would be as pure as any angel free to go in and out of His presence. Tell me why she could not and why she would need a savior, as she explicitly said she had. If she had a savior when she did not need one, that makes no sense.
After you think through that one, then tell me why Jesus suffered in the garden, begging the Father for any way man could be redeemed so He did not have to suffer being separated from the Father, if all God had to do was simply remove original sin for people and leave them to their own devices. That way you could be "good enough" completely on your own without the need for a redeemer, just like you claim Mary did. After all, if she could do it, so could everyone else and there would be no need for Christ to die and resurrect Himself.