According to Sikh traditions, death is not a time for mourning, but instead a time for gathering, remembering and celebrating. Simran Jeet Singh, The Sikh Coalition
The Sikh tradition (Sikhi) gives no clear explanation on what happens to people when their lives end. Sikhi does not place emphasis on afterlife, and instead, encourages people to focus on what can be achieved within our present lives. According to its religious teachings, this human life is a unique opportunity to connect with the Divine, to realize our potential, and to serve those around us.
This is a useful website article that explains how Sikhs comfort the dying, mark death, comfort the bereaved and celebrate life.