If the keyboard has an electrical or mechanical defect, you may use
an external keyboard (wired) while at a desktop work space.
Not sure if you could re-select one of the F- keys in the Keyboard
system preferences, where Keyboard Shortcuts may be used or
modified. ~ Perhaps there's a 'Mouse-key' option in Accessibility?
You may be able to selective use of 'Keyboard Viewer' where you can
click on a Letter within its tiny keyboard panel when open on screen
to make use of that access point. In an older Mac I'm using right now
the Keyboard Viewer if not already in the Finder menu bar (near clock)
can be turned-on in the System Preferences> International> input menu
where language choices and other items appear. The 'Character Palette'
option can be enabled from same location. (this reference, in 10.5.8.)
Good luck & happy trails! 🙂