sponsoring my brother

I already sponsored my parents for green card in Jan 04 and they wil get call in next 6 months.
Bt I didn't sponsor my brother at that time.
he is only 19 yrs old.
Is it too late if I apply for him now.

Sponsoring siblings takes 12+ years. This is family category 4, so unlike for your parents, there is a quota.

but I heard that when parents are sponsored for GC any siblings below the age of 21 can also be sposored.
then it is easy for them to get VISA too.
Is that true.

As far as I know, this is not true.
It would be true when sponsoring a foreign spouse, but not for sponsoring parents.

[immihelp]

When you are sponsoring your parents, if you have siblings are unmarried and below 21, they can come along with your parents and get greencard at the same time.