Let my mom pass away fast, or live longer if I delay to go back

As long as I stay in USA, she would like to take medicine and wait for me. However, if I go back right now, she will pass away very soon, because she will stop taking medicine after she sees me.
By the way, one of my best friends is a doctor, often goes to see my mom at home, and tells me about my mom's current health. When he tells me it is diificult to maintain her life, I will immediatelly go back to China.
That's OK? or I should go back ASAP.
Thanks.