Why does the questioner think about death daily and always, fear for his future and the future of his family, and wonder about the reason some people die in tragic ways, and can the answer help him get rid of these thoughts so he can live a happy life?

The praiseworthy fear of death is that which motivates one to stay away from sins. As for the blameworthy fear, it is that which causes panic and discourages action. To overcome the obsessive fear of death: feel that death is a divine decree and destiny that cannot be repelled, and remember Allah's mercy upon His servants, and that death is the key to Paradise for the believer. Rely on Allah in all your affairs, and start your life with activity and certainty, and know that Allah has guaranteed the sustenance of His servants. Increase in supplication, and know that the manner of death does not indicate the evil of the deceased, for righteous people may die in accidents such as drowning and collapse, and Allah raises their ranks thereby.