Conclusion: 

In most of the animations, the mother, as a character, is

not only a figure of someone who raises her children and or someone

who does chores for the family but more importantly, a protector

or supporter. Thus, the loss of the mother is a sign that the family loses

some protection, in other words, the family would need more protection

to fill up what is lost, like the movie Despicable Me and Finding Nemo,

the father steps up and acts as a stronger and a more responsible character

in his family to protect it. However, there are some plots that the characters who lost their mothers starting protecting themselves and their loved ones. 

In addition, the mother is also a figure of love that asks for nothing, like the

movie Coraline, the main character Coraline realized how her mother loves

her and the true meaning of being with her mother after leaving her to another idealize family.