I have a baby in heaven, and I do a lot of peer counceling and outreach. I run across that lack of distinction a lot. Many times it originates from someone who is not Catholic. I also think that sometimes there is a blurring of the lines between what is our actual faith and what can be a comforting thought. In loss circles, it is common to refer to the date of death as the “Angel Day” As a Catholic, I have to stand back and realize, no my baby is not an angel, but he lives with the angels.
I don’t fault people who refer to their babies as angels, I think of it sort of similar to a vernacular…not standard English, but a common usuage. I’m sure more orthodox Catholics would stand more firm, but I for one am not going to tell a grieving mother that an image that brings her comfort is not correct.