Parked overnight now truck doesn’t start.

[SquareOne]

Typically a weak starter or solenoid will click followed by pulling down 'good' batteries substantially. Was that 11.6v reading with the key-on only? If so, that's too low to begin with. Like Rawze mentioned, check the headlamps (brightness) and the measured voltage. That would be a good start on battery health.

When is the last time they were checked or replaced?