Based on your update, OP, I suspect the tech is not the big issue -- it's tech plus sudden motherhood plus lifelong social insecurity and/or avoidance. Triple brain-freeze, anyone?
All of the advice you've been given on the tech aspect is great. If she is at all motivated, she may eventually work her way past constant confusion.
But maybe the missing piece is for mother and son to find another way to relate. Could there be a mutual interest or activity or topic of conversation that they both enjoy? I say this knowing it could be a mountain-high challenge to find such a thing.
Conversely, MIL may come around if she can be assured that there are no big expectations on her son's end, just acceptance of the past and, hopefully with time, enjoyment of a present and future at a level of closeness that works for all of you.