But that's just guesswork, we don't know who is more attached to whom. For all we know Manu could be more attached to his Mother. Even if we cite the Piku incident where he supposedly lost it, he still didn't physically assault Om either or jump after him the way Bani did. Her reaction was an extreme one.
Yes Bani's reaction was more intense than Manu's. Her mother is her weakest spot. And as everyone knows it very well now so hitting it again and again.