Sending, receiving, and organizing email in Outlook.com
This behavior is caused by how Outlook suggests names and addresses when composing mail. Outlook keeps a history of recipients that have been emailed before and uses that to auto-suggest names, even when sending to the same email address.
In this case, the email address is correct, but at some point that address was associated with the child’s name in the suggestion cache, so Outlook now shows the child’s name for that address in the From/To suggestions and in Sent Items.
To address it, remove or correct the cached suggestion for that address so that the correct display name is used going forward. After clearing or fixing the suggestion, type the email address again and send a message; Outlook will then store the new, correct name with that address for future suggestions.
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