how do i deal with tantrum toddler instead of using hitting her

I have seen my nephews (age at 1 yr & 2 yr old) being scolded by the mom and disciplined by the dad. They are not afraid of the mom cause what she did is just shout at them or hit them to stop doing what they are currently doing without telling them why. The dad will give them a stern lecture n ask why they fight/snatch things before punishing them (stand at one corner and out hands up instead of hitting). The outcome is they tend to listen more to the dad. Even thou the mom seems to be more fierce and often screams at them.