How much should I try to sue for the death of my grandmother?

My grandmother was living at an istant living facility. She had walked out an emergency exit with summer clothes on. The exit alarm was deactivated resulting to her being locked out side in the cold weather. My grandmother was diagnosed with Dementia 3years ago. She walked a quarter of a mile from her house and died by minor injuries and hypothermia. The temperature was around 23 degrees that morning. A similar situation had happen before during the summer and the issue regarding the emergency exit alarm was addressed but never attended to. I’m trying to determine how much I should attempt to sue for and what can be done to prevent this from happening to someone else. How can you put a price on a life of someone you loved or any life?