Q: Did mechanic not refill radiator when doing flush?

Car was flushed in Oct. Started driving it in mid December. Heat wasn't working. Got actuator changed and it worked really good for a couple of days. Then started to only work when accelerating. Maybe a week after driving it, it wouldn't start a couple of mornings when it was cold. Then suddenly it started reading that it was hot. A little more than half way up the dial. No steam or anything but I stopped driving it thinking it may be thermostat. Got it changed. My dad did it. He's old and couldn't get clamp on hose, although he to tried. Drove him down the road a couple of times and it over heats. This time I'm pretty sure it was the loose hose. Antifreeze was leaking from it. However, we put a gallon of antifreeze easy. Behaved long enough to take him home and get myself more antifreeze. Put another gallon of antifreeze in. Dad thinks its possible I didn't need a thermostat, that I could have been that low on antifreeze. Think I would have notice losing two gallons of antifreeze wdyt

My car has 95000 miles.
My car has an automatic transmission.