2006 Hyundai Tuscon Caliper Fell off

I took my car in to get new pads 7 weeks ago. About three weeks ago I heard a rubbing sound coming from the rear passeneger side. On the way home tonight I lost my brakes and nearly crashed. I opened the hood and noticed I did not have any brake fluid. The rear caliper had fallen off. It was still there but the piston was half way out and fluid was all over. Should the mechanic be liable ofr this caliper falling off?