Why does the brakes stay on after I release the pedal?

Check for a bad or stuck caliper. Also, check rear brakes to make sure none of the retaining springs are broken. If all looks good, the rubber brake hoses to the calipers could be bad inside allowing you to force fluid into the caliper to stop, but not allowing the pressure to release back to the master cylinder. Usually, the brake pads or shoes will wear very fast if that is the case on the affected brake.

Since ABS light is on, you could have a bad ABS pump which is not allowing the fluids to return to release the brakes. Try releasing the pressure from the caliper and/or slave cylinders.