Hi there arosebud,
We understand you aren't able to see a specific friend's location through iMessage, but can with Find My. We have some suggested steps to walk through that could help. Be aware that the issue may be on your friend's end and they may need to troubleshoot as well, or reach out to Apple Support. We'll include the information at the end of this post.
For both devices:
- Go to Settings > General > Software Update and install any available iOS updates.
- Force quit the iMessage app.
3. Restart your iPhone
4. Test sharing the location again.
Have your friend confirm no one else they share a location with through iMessage has the same issue. This will rule out if it's more on their end or yours. To contact Apple Support, you can reach them here: Get Support
You can also find the support phone number for your region at this link: Contact Apple for support and service
Take care.