“If I go through with this I lose my mother. That is not a theological problem, and no argument about the Qur’an touches it.”

You are right that no argument touches it, and anyone who answers this by handing you a verse has not heard what you said.

This is the most common thing in the accounts of people who have left, more common than any argument about scripture or science. What surfaces again and again is not a refuted doctrine; it is a mother's face, a house one is no longer invited to, a grandmother writing letters. Older apologetic writing brushed this aside as though being cut off by one's family were a minor detail. It is not a minor detail. It is usually the whole weight of the thing.

Two things can be said honestly. The first is that the rupture you are imagining is real for some people and not for others, and you cannot know in advance which you are facing. Families surprise people in both directions. The second is that this cost is separate from the question of whether Islam is true. If you become convinced it is false, the cost does not make it true. If you remain convinced it is true, fear of that cost is a poor reason to stay, and a faith held to keep the peace at home is not the thing this site is defending.

What you should not do is carry this alone, or let the size of it force a decision either way tonight. Talk to someone who knows you and is not invested in the outcome. If there is a person in your family who has ever been gentle with a hard question, start there.