Bhai Sadhu was a Khosia Khatri of Malla, in present-day Faridkot district of the Punjab. He was married to Bibi Viro, the daughter of Guru Hargobind and elder sister of Guru Tegh Bahadur. Thus he was a phuphar, one of the Punjabi words for uncle (father's brother in-law) of Guru Gobind Singh. Bhai Sadhu had 5 sons; Jit Mall, Gulab Chand, Sango Shah, Mahri Chand and Ganga Ram. Guru Gobind Singh's autobiographical poem Bachitar Natak, mentions that all 5 sons took a heroic part in the battle of Bhangani (18 September 1688) that was fought near Paonta Sahib, now in Himachal Pradesh.