Bernie is the oldest of the four Bryant brothers. Bobby is twice as old as Billy, but 2 years younger than Bernie. Bernie is twice as old as Buddy. The youngest Bryant brother is 6 years old. What are the ages of the four Bryant brothers?

Let's start with Buddy, let his age be x

"Bernie is twice as old as Buddy"
Bernie is 2x

"Bobby is 2 years younger than Bernie"
Bobby is 2x-2

"Bobby is twice as old as Billy"
Billy is 1/2 Bobby's age or x-1

looks like Billy could be the youngest, so
x-1 = 6
x=7

Then
Buddy is 7
Bernie is 14
Bobby is 12 and
Billy is 6