Even though Jesus is higher than angels (ch. 1) the author of Hebrews strives to point out that He is also just like us (ch. 2)!
"Brothers and sisters" is the term applied to our relationship with Jesus (vs. 11, 12, and 17). Jesus, the Son of God, took on flesh and blood in order to make us sons - and daughters - of God.
Hebrews explains that He accomplished this through His suffering. Jesus suffered everything that we do, and even suffered to the point of death to break the power of death.
Because Jesus suffered, He is able to help us who are suffering!