Question about family

Lately, my family worrying about their grand children everyday with my older sister and her husband how they treated them mean and yelling and screaming at them and my older sister husband is just yelled at them, they don't treating them with love and affection, I never seen him playing with them and hugging them, we look at him he looks like very evil and dark person, that he just thinks about material realistic stuff buying houses, thinking and buying newer cars like Lamborghini, audi, heck I bought him a acting class aka master class and they thinking moving away to Utah, something fishy about that, I don't want them to move from my mom and my dad and the family.

because we have family in arizona, that we are close to.

Me and my family can't stand him, he thinks that he is very smart, he just stupid and dumb.

Plus he doesn't like any of my family, like my dad's family and always complaining about them saying stupid things about them.

His family move away from him, they know something is wrong with him.

When we Vist them or they visited us

We have to play it cool and all.

Plus he put salt and pepper on my mom's birthday cake back In 2019, and in 2021 he almost burned down My family house and broke my kitchen aid and ruined it.

He is just pyscho person, which he needs get serious help on his life, before it's too late.

What me or my family should do.