Not sure if I understand your question, but the building code in Montgomery County requires that a threshold for a door can be no taller than 1 1/4". You can measure the threshold that was installed, but in all likelihood it probably meets code. No door threshold would be manufactured that wouldn't meet code. If the threshold height is a problem for your mom, you can try to see if they can install a low profile, handicap threshold that might be easier for her to get over.