Upanishads say – You can’t conquer the fear of death through activities. There are some karmas to extend life – like Shantis. Shanti is to make ourself peaceful – to accept life as it is.
They should we not do good work? Upanishads say – do the good work as though the other person is no different from us.
There are three stages of fear –
1. Bhaya – having the fear of death
2. Nirbhaya – trying to overcome / conquer the fear of death
3. Abhaya – the opposite of nirbhaya, a state of true fearlessness, with the acceptance of death