I was recently asked to aid in serving communion in the non-denominational church my mother attends. Is this permissible?
Your profile indicates you are a non-denominational Christian who is in RCIA. Some enter RCIA just to learn more about Catholicism but without intending to become Catholic. Others are preparing for reception into the Church. If you are preparing to become Catholic, then now is the time to begin ending your involvement with the non-denominational church you attend with your mother. If your mother needs you to take her to church, you can do that, but you should begin to act as a non-participating guest. That would include politely declining to distribute a communion that the Catholic Church views as objectively invalid.