The parents will be very quick (about 9-12 months).  The brother will take about 10-12 years so the process, while similar in terms of the petition itself is very different in terms of the wait times.  The uncle's petition could help your parents if the priority date is very close and you would not have to petition for your parents.  However, the brothers will not be able to immigrate on the basis of that, most likely, since they have aged out when they turned 21.