Let me clarify myself. I am not saying she committed a crime. Even according to Islam a son is allowed to shift from his parents house after getting married, just like he is allowed to marry 3 more women, but if any of your’s husband marries another woman, you will be crying buckets and you will call him a cheat and a fraud. A women in an arab country, on the other hand, will be perfectly ok if her husband marries another women, because its quiet normal there. So you see, its all about the culture. Culture shapes your feelings.
Yes MIL was mentally prepared. And btw it isnt like her MIL is badmouthing her or anything, she is just sad, are you blaming her for that?
And yes obviously my friend MADE her husband leave her parents, why else would he leave them. And they had a big house, with lots of bathrooms, dont you worry about that.