I have a 70 year old dentist client who is having problems with his A13 key system. Some of the phones don't work. He expects to die soon, so he doesn't want to buy a new system. As a self-supporting phone tech, what would you do for him?

I know the A13 uses two pairs of wire, so installing a Partner system is one possibility. Another is to install plain old two-line phones. What do you think of these options? Any other suggestions?

Vaya con Dios amigos!
Butch