A man who threatened his sister with an ax will serve four months in jail and have to undergo a mental evaluation.The man, John Austin Graham Curtis, 20, had a felony count of aggravated assault reduced to domestic assault and was directed to serve 120 days of an 11-month, 29-day sentence. Circuit Court Judge Bart Stanley also directed him to attend batterer intervention along with undergoing a mental evaluation.The incident which landed Curtis in jail happened just before his 20th birthday in April. His sister, the victim, told police the siblings had been arguing.