Communication Of Family Is Important

Yesterday, i had a drink with a friend.
He was very anger to his sister.
The different of age between my friend and his sister is quite a long distance.
Maybe cause of this reason, their communication is nt so good, i mean sometimes.
Now, what's wrong with them? His sister talk loudly to him when he was going to start his car.But 1 thing, not the false to speak loudly,just because her words sound like 'have thorns behind the words'..The way she talk.
This is what my freind doesn't like.
my friend told me this situation not just happened once, quite many times his sister talk like that to him.
Maybe cause of lack of communication between them, the same situation happened and happened again.Her sister always no ask for fact what my friend did, and just scold him without any proof and just follow her own view.
Although i cant understand his feeling so much, but based on his case,
i felt that the communication between family members are much important then others.
As a result,
if we always communicate and empathize to our family members or even freinds,we can avoid arguement and the unhappy situation to be happened.