If your brother have completed the exit formalities (even though not serving notice period) of that organization.
then he can get the certificate from HR.
In other case,
If the organization have reported him as absconding and terminated the service.
Then experience certificate or relieving will not be issued.
It's a general practice to not issue experience certificate for absconding / service less than 3 months.etc
In future, when he gets into a job and when reference checks is done, if the organization reports him as absconding and
terminated the service, will be a bad mark for him.
13th February 2014 From India