Every person creates his / her own destiny. whether I go to heaven or hell, whether or not I will get a good birth, or whether or not I will attain moksha (deliverance from the cycle of birth & death), is entirely dependent on my actions and not on the rituals perfomed by my children after my death.
There are 3-4 ways by which a person may face untimely death during his lifetime. Such untimely certain death (Gandantar) may not be prevented even by the bestest human efforts. Only the Parmeshwar (the Almighty) can avert such a situation.