Albert, if I understand well your position regarding angels is the following:
On the basis of your personal experience you support the existence of guardian angels as protectors of human beings. Similarly you accept as unequivocal “Gabriel’s announcement of Mary’s pregnancy”.
So you don’t deny the existence of angels.
However you seem to deny that a multitude of angels existed prior to humankind’s creation.
And you seem to maintain that there was no sin on the part of angels.
As I have stated in previous postings we are unambiguously taught by the New Testament that:
Angels are pure spiritual beings, and therefore endowed with free will.
They were created by God to freely worship Him and in particular Jesus Christ as incarnated Son of God.
Satan and other angels rejected to worship God, and prowl tempting humans to do the same.
You yourself quote Matthew 4:1-11. I agree with you that this account was narrated by Jesus to his disciples. Nonetheless I disagree that this episode refers to sort of “delirium”. I think rather it was reported by Jesus Christ in order we learn from Him how to resist devil’s temptations.
The two episodes Matthew 4:1-11, and Luke 4:1–13, are completed by John 8:44 and Ephesians 6:12. And all these pericopes together are crucial to interpret the temptation of Adam and Eve in Genesis 3.
If you really wish to motivate your great-grandson for reaching eternal life as a follower of Jesus Christ, then it seems to me the best thing you can do is to recommend him to read the Gospels. He will undoubtedly meet the passages where Jesus Christ speaks about angels and will have to decide by his own whether he freely accepts or rejects Jesus Christ’s teaching in this respect. In my view it would be counterproductive trying to downgrade as “mere figurative” parts of Jesus’ teaching in order he accepts to be a Christian faithful. In particular, this would be a heavy burden for the relationship with the Christian faithful girl your great-grandson is dating.
Once again: Consistency with science doesn’t preclude thinking seriously about angels.
No serious theologian has ever discussed the question: “how many angels can dance on the head of a pin?”
By contrast Thomas Aquinas asked the sound question “Can several angels be in the same place?” And he gave a sound answer to it.
You say that your great-grandson excels in computer science and is motivated by a career in artificial intelligence. Notice that in the light of today’s science the universe can be considered an ongoing immense quantum computation. In whichever way you look at this, you can’t help accepting powerful minds performing this computation from outside space-time. Accordingly, Aquinas questions on angels could be updated as follows:
“How much computational power is required to compute the universe we perceive at any moment?”
And last but not least: We can pray the guardian angel of your great-grandson to help him as well as yours helped you!