What do you want?
You wrote your landlord is not paying the mortgage + not making repairs.
Depending upon how far the mortgage is in arrears, the house may go into foreclosure if it isn't already, so any repairs he makes won't help you for long.
Again, what do you want?
Given your description of the problems you face (if it were me and I were you,) I'd want to move. If that's what you want, tell him so. Lease or not, depending upon what's wrong with the house - he may legally have to let you go.
Here's a link to the Arizona Department of Housing (ADOH) where you can download a copy of the Arizona Residential Landlord Tenant Act.
Read it and show it to your landlord.
Best of luck!