Replace Dead Latch/Lock for Jeld Wen Premium Atlantic Aluminum Bypass Sliding Patio Door (6800)

I agree, our 82-260 looks like the best choice for your mortise lock. As for it not functioning properly, it's possible that the issue is with the thumb lever. A good way to test this is to remove the handle from the door entirely and try throwing the mortise with a screwdriver. If it still doesn't work properly, then the mortise is the issue. 

If it works fine, however, then there is something wrong with the handle set. While you have it off, look for any kind of damage that might prevent it from working properly.

Sure, one common option is our 82-106. Now, I'm not 100% sure if this is compatible with your handle, but I think it's worth considering. It very well could be. I can at least tell you that it is compatible with the 82-260 and is used for many handles in this style, like the 82-069 or 82-035.