I don't recall it displaying the distance for people I follow in kilometers. I'm pretty confident it used to show in miles. Has something changed or is there a setting for that?
I do not use the Find My Friends app, however, according to Apple, you can easily change it back to miles. See the following link.
https://support.apple.com/kb/PH19444?viewlocale=en_US&locale=en_US
You're very welcome, sir...Perfect that was it! Not sure how it got changed but all fixed now. Than you!