I have downloaded the zip on my son's phone but it's not usable. - does anyone have suggestions he really likes the fonts.  The error messages states there are not any apps to open fonts.  What app is applicable to it for use on his phone 

You can use the free OpenDyslexic app to install OpenDyslexic on iOS.

Installing fonts on the iPhone is done differently than on most other platforms. Instead of opening a font to install, Apple requires a provider of a font to create an App that installs the font. Removing the app also removes the font.

On Android, there is no method for installing fonts, but many apps have their own individual methods of recognizing a font they can use.