You mother asked you what other religion is obeying the commandments of Matthew 24 and Matthew 28, if not for all the preaching done by various Christian groups and churches over the last two millenniums, Jehovah's Witnesses would not exist today. Did your mother realize that there is no country on Earth where Jehovah's Witnesses have been successful in countries that did not have the seeds sown by various Christian Churches?
The facts and evidence and internal and extrenal books and documents in the Watchtower Society show they have had no meaningful gains in Islamic Countries! Their message has only grown in Countries that ancient Christian Missionaries and Preachers worked at for hundreds of years. Please ask your mother, which country has the Watchtower Organization been successful at that had no influence by Christendom? Iran, Iraq, Pakistan, Saudia Arabia, Burma, Somalia, Yemen, ect.....
Jehovah's Witnesses have never been a religion to head into a country where preaching is going to get their Missionaries backed by Bethel be-headed! Ancient Christians of the Catholic, Protestant, Mennonite, and other Baptist groups were bold and pushed into countries were it was illegal and very costly to preach the Good News!
Why do we really bother because nobody is ready before their time to learn the Truth. Too many elderly are willing to die with a lie than face the fact they were following a hoax their whole life I am so sorry for you, she think's she is doing the right thing as she fulfills Christ's prophecy that people would deliver up to their church thinking they were rendering a act of worship! Nothing matters with somebody who has their eyes crazy gluued shut!