1)
Why did Yehu kill the sons of Achazyahu's brothers, and not his brothers themselves?
1.
'Rashi': Above (21:17), it says that Pelishtim and Arvim killed his brothers; only Achazyahu remained.
2)
Here it says that Yehu killed the sons of Achazyahu's brothers, and a troop of Aravim killed Achazyahu's brothers (verse 1). In Melachim II, 10:13 it says that Yehu killed Achazyahu's brothers!
1.
Refer to Melachim II, 10:13:2:1.
3)
How were they serving Achazyahu?
1.
Radak: They were going to help Melech Yisrael, like Achazyahu commanded them.
