Please. Please explain to her that it's not that type of affection ><
I'm not really keen on people "falling in love" just bcos the person looks like their mother, especially if that mother is dead. Otherwise it will be a child/mother type not a real partnership. But at the same time, I sympathize with him for wanting affections of a mother.
So please, let him be another son for her like the siblings, instead of a lover T^T