Mercer sliding glass patio door handle and lock are broken

Hello!

Take a look at our 82-032 handle set with 3-15/16" hole center spacing and compare our dimensions to yours to see if this matches up to your original handle. As for the lock, I can quite tell what you have from this angle. Can you show us a clearer view of your mortise lock?

Thank you!

The part you're describing here is called a keeper. The bad news is that your mortise is compatible with about a million different kinds, and without the original as a reference I can't be sure what would be the best fit for your door.

If I had to guess, I would say you need something like the 89-029, but it's important to keep in mind that this is just a guess. 

As for the mortise itself, I cannot tell just by looking at it if it's broken. As long as it works then you can keep using it.

I believe a #8 sized screw would be sufficient, though I do not know how long it would have to be. That depends more on your door than the keeper itself.