If the computer did not come with disks, chances are it has a recovery partition built in.
This takes the place of the disks.
See if anything here will help you access the recovery partition. (if there is one on your system).
If for some reason you don't have one, see if your brother does. If his has it, you can create a set of recovery disks to use since you both have the same system.
I won't comment on the cloning because I have no knowledge of that. Someone else will have to advise you about it.