When my wife miscarried in 2020 we stumbled across (someone may have recommended it, but we cannot remember who) a children’s book called The Moon is Always Round. I cannot recommend it more highly.
It was near impossible to read to my family the first time, but we pressed through in a mournful, sobbing 20 minute read. The next time was easier and, as God’s Spirit helped us, the book helped heal and comfort us.
My recommendation is to get several copies of this book at the ready for your people. I am sure it will be a help.
There are other resources that are helpful - but this was the most practical way to talk with my kids about their sibling they did not meet and the grief they saw in their parents and felt themselves.
Are there other particular things you have done, given, prayed, etc. that you have found to be particularly helpful for miscarriages?