Thank you for detailed reply i got directly information from USCIS and they confirmed that the person can live for no more than 364 days. But he/she need to give the reason on arrival which could be anything like medical condition etc.
Thank you everyone for the reply but what about this . It says she can be out upto 12 months. https://help.cbp.gov/s/article/Article-820?language=en_US
My mother received her Green Card in March 2022 and then travelled back to Pakistan in May 2022. Since then, she is in Pakistan. I wonder how long she can further stay in Pakistan. is it 12 months?