Sounds a lot like me albeit with "girlfriend" in place of "daughter." Bonus point in that without regular iron infusions and other modern medicine her life expectancy gets very short...The scenario where my daughter is a confirmed death.
In that case, I have little reason to carry on - depending on the cause of death, I would probably just do nothing extra to survive if at all. If someone is to blame for her death (negligence, malicious, etc.), then I would probably seek extreme retribution without regard to my own survival or consequences, if at all possible.
If she is missing/etc., I would do whatever I could to search & rescue, if possible - but I could think of a lot of scenarios where she would be missing and there is nothing I could do.