I have puzzled over this for years. Whilst I believe that she thinks she had a religious experience when tow young Mormon missionaries knocked on the door, after much consideration I think I know one of the reasons that she joined the Mormon Church.
She was lonely and isolated. In early 1960s Birmingham was still a city terribly devastated by the Second World War. Vast sections of the city were still officially declared bomb site. It was weird. You would walk along a road and, although the gaslights were still in position and still burning (yes, Birmingham still had gaslights in the street into the mid to late 1960s!) one or both sides of the cobbled street were totally flat. The corpses of some people had been left in the cellars of the engineering works or the houses in the tightly packed back-to-back housing in and near the city centre, where we lived.
The government decided it would be too costly to rebuild, so they had new towns built and large sections of the populace of Birmingham were forced to leave our home city and settled in these new towns.
My mother was given a choice of three. And chose the worst option, as it happens. We were used to a bustling city with 24 hour a day bus services, theatres, cinemas and train services and relatively high wages with skilled jobs. We moved to an area of a few buses a day to the nearest town, no train service, no cinema and no theatre. And wages 1/10 of in Birmingham. And no skilled jobs.
And the local people hated us. They reviled us in the street and called us names. I was at school, my father had to make an 80 mile round trip to and from work and my mother was at home, isolated and so very, very lonely. And she knew that the situation we were in was partially her fault, for opting for the wrong area.
The other members of the church she attended resented her, as she was an incomer, so not welcome. Some people were kind, but many were not.
And then the Mormon missionaries came. Clean, nice looking young lads. They came with tales of a golden bible, and of Moroni’s promise.
She went to church and felt welcome for the first time in the area we lived in. That clinched it, I think. Also, it might have been a sort of black humour of sorts that lead my mother, isolated and persecuted as she was, to choose to join a church which liked to exude an air of pious beatification as it exaggerates one or two stories of early persecution into a skein of lies that cocoon Mormonism from the real world.
Perhaps my mother identified with Mormons and Mormonism because she felt she was suffering, as the church were? And after all she was persecuted for being a Brummie. Might as well make it something more interesting to be persecuted of. Like being a member of a loony cult.