What Causes Vomiting Spells And Temper Tantrum Post A Craniotomy Procedure?

my son had a hemographic stroke and craniotomy on June 28th He could speak and walk immediately after and he went to rehad for a few weeks and went back to office job on October 23rd. He got fired from his high stress job on Dec. 16th. He seems more emotional and sometimes irrational and has anger issues. He sems to have slipped backward. He has had some severe vomiting spells over a period of the last few weeks, no appetite and has lost weight and easy to anger. Is there a chance a complication has arisen from surgery. He was called the miracle man and expected to recover. His short term memory is not good and now it seems more difficult to perform some simple tasks than when first in recovery. YYYY@YYYY