I have a 1962 Eichler. in Sunnyvale The plastic lever used to lock/unlock the sliding glass door broke off. I'm told they are no longer made. Does anyone have - or know where to get- a used handle/door?
If all that is broken is the small plastic piece that you rotate to lock/unlock the door, some glass shops have parts that will do the trick.
If your doors are made by Arcadia, you can order replacement parts directly from them. The piece is called a latch actuator and costs $17.50.
Do a web search on Arcadia products and then look for the replacement parts listing...