Thank you for posting your query.
Left side of brain controls the speech and motor function of right half of body. As a result of damage to this area, your brother has speech difficulty and weakness of right arm and leg.
Unfortunately, there is no medication that would help in recovery of these functions.
Regular speech therapy
over a few months would lead to partial recovery, but complete recovery may not be possible.
Dr Sudhir Kumar MD DM (Neurology)
Senior Consultant Neurologist