I have skimmed through the manual and come up short.
I can tell you the red light is indicating the security system is set/ready.
So, with your fob buttons not working you just unlock the door with the key. Has this security system been disabled before? Maybe something a dealer has to do.
I know if you use the key to unlock the door and the alarm goes off, you can put the key in the ignition and turn it and the alarm will quit. I know you canīt do this everyday, that will upset the neighbors, so how have you been doing this before the battery replacement?