Why does the son have to order for her when she has every right as a citizen to order her own food with dignity?
Bring disabled doesn't make you immune to criticism, but there's nothing to criticize in her actions. She went to the drive through to order food like she is legally and ethically allowed to do. If the employee had done his job correctly then there would be no boiling point to take advantage of. The situation only occurred because the employee did the wrong thing, which is why he was fired.
Without her son filming this discrimination, there would be no evidence for her claims that the employee was being a piece of shit who was violating the Americans with Disability Act.