If one 'sees' a vision, there is nothing there for him to 'see'. It's a vision. This is what Peter, James and John experienced at the transfiguration of Jesus when they 'saw' Moses and Elijah. Moses and Elijah weren't there. Moses' and Elijah's 'spirits' were not there. P,J and J had a vision. I can't say for sure, because I don't know--but it may be possible to actually 'see' Spiritual-beings such as angels because they actually 'appear'. God, on the other hand, IS Spirit and He cannot be seen. Jesus Christ is the express image of the INVISIBLE GOD.
There are phenomena mentioned in scripture that defy every-day experience. I've experienced some myself. AS BEST AS I CAN SEE, there are very few (if any) of them that are meant for believers. All (or almost all) are meant for unbelievers. If such a thing happened to your mother, or to anybody else, we can be sure it was by the will of God for the purpose of God. He is sovereign God, after all.
Yet we also know that it is by the will of God and for the purpose of God that the great majority of mankind is blinded. As a practical matter, many such phenomenon can be explained 'naturally'--and many more are intended to decieve from the beginning by hoaxsters and charlatans. That doesn't mean that some are not 'genuine'...just that not all are.
Given all that, I don't want to spend my time looking for, wishing for, or expecting 'events' not meant for believers and open to manipulation by men and spirits. This is why I take it fairly personally when I'm encountering people who seem to be wanting to impress me with their visions, etc. They are asking me to lay aside the miracle that was worked in MY life (to be 'unblinded' and to begin to see Scripture with spiritual eyes) in order to give attention to, at the least, 'dubious' events in their life--often interpreted in religious context that has nothing to do with Scriptural, Spiritual truth.
I've lived my life, and still do. I've had experiences outside the normal day-to-day routine, as has your mother, you, and probably most of the people reading this thread. These have helped shape my life by the will of God and played a part in preparing me to believe the Gospel. So have sin, Satan, religion and every other 'cause' that He's used to herd me "here". Now they are in the past and I'm moving on to the Higher Calling. The only sign and wonder I'm looking forward to is resurrection.
That's my take.