MK rear brake question

MK 4 rear brake question

The orange brake warning light is on, on my dash.

Not sure what is setting it off as I have enough brake fluid and there is pad material on all four wheels.

The only brake issue I have is the hand brake does not work or move. My step son drove the car earlier with the hand brake on until smoke was pouring out the rear which was the original cause of handbrake issues.

My question what needs to be fixed to fix handbrake issue? Will this cause the brake warning LED to go out?

The orange light is for the brake wear sensor on the front left wheel. If it's on, either the pad is low, or the wiring was damaged.

Alarmingly the brake pad can come unglued from the backing which causes the light to turn on without showing signs of being depleted. if the light is on, its the front driver side inner brake pad.

Thank you all for your responses. You've been very helpful.