I think people can imagine it being an angel..they do exist and are detailed throughout scripture.
but what strains belief is the thought people die and become angels to come back here...like a priest who died 45 years ago...
Those could be a good example of what the bible describes as a demon appearing as an angel of light... fatima comes to mind
I don’t think it was a demon.
A gentle correction is in order.
The angels and the saints, those who have gone before ahead of us, support us in this life not only by their prayers of intercession, but they can and do come to earth called “apparations”.
I second what Salvation said. This was an angel.
I absolutely agree with you, people can’t come back from the dead nor do they know what we are doing, including Mary and the saints.