Just tough love or too harsh?

Amelia

My sisters son (6) has issues with still pooping and peeing in his pants. He was held back to pre-k last year because of it. They have had him checked out to rule out any medical issues and the doc pretty much told them that his problem is he is too lazy to get up and go when he needs too.

Well today he pooped his pants while a bath room was literally 5ft away and never said a word until she asked about the smell when they got home. So she proceeded to tell him that if he was going to poop his pants like a little baby then she was going to treat him like one. She walked him through the house by the hand to the bathroom, took his clothes off and got him cleaned up and got him dressed the whole time calling him little baby instead if by name. The boy had a pretty good rash so she doctored that and then sent him to bed. I saw no problem with her method as i know she has tried others as far as punishment for this behavior. But her mother in law chimed in that she was being mean to him and shouldn't resort to humiliating him like that, she said he is not a baby and shouldn't be treated like that. She even yelled at the older boy when he complained about having to pick up his brothers soiled clothes. My sister is expecting another child so i can see why her 6 year olds behavior is frustrating to her and i don't feel she was in the wrong and that her mother in law had no right to tell her how to raise her children. But we were raised through tough love so maybe i am being biased. Is what she did tough love or just mean?