Slider Lock Is Broke
Hey there, thanks for reaching out! I'm sorry to hear of the trouble you are having with your door, however, we will try our best to guide you with the best solution to repair it.
It sounds like either the mortise lock or the handle is broken. With that said, the first step will be to remove the handle entirely so that you can access the mortise lock. Once the handle is off, there should be several small holes in the door frame; the mortise lock will be visible through these holes. You'll need to search for a 90 degree slot.
The second step, will be to try to turn that slot manually with a screwdriver. This slot is what locks and unlocks the door. If it just spins, that is not a good sign. This indicates mortise is broken and will have to be cut off the door frame. It is highly recommended to have a professional do this.
However, if the mortise does unlock with the screwdriver, you're in the clear! they dodged a bullet.
That will make it easier to began working on identifying the handle replacement.
Please take a look over these steps and try them out to see where we are in the repair process.
Feel free to reach out with any questions you may have in the meantime.