Help identify very old sliding glass door handle

Hello there! Thank you for reaching out to us. I'm sorry to say we don't sell a replacement or alternative for the handle set shown here. Nothing we have would be compatible with the mortise lock, unfortunately. Your best bet may be to consult a local professional to see if they can adapt something to this door. I sincerely apologize that we can't be of help with this repair; please let us know if you have any other hardware questions.