When I install Ancient Warefare, it works fine, up until the launcher opens minecraft. Then, all the text in the menu and in game is symbols instead of letters and I have no idea how to change them to something I can read, or if it is possible to fix. The same download for ancient warefare works perfect on my PC but not my Mac.

Try clicking the little globe button on the main menu, and try changing the language.
Other than that, I don't see much possibilities for a fix, unless one of the remaining developers happens to see this

Impossible to be related to the mod.
Find a Forge version that doesn't screw up your font on mac.