Here is an old writeup on Bau Mal Singh jee, who was the life long companion of Bhai Sahib Randhir Singh jee.
Bau Mal Singh jee was a great Gursikh who was a life long companion of Bhai Sahib Randhir Singh jee. Bau jee and Colonel Pyara Singh used to do bhagti of Naam abhyaas together. Bau jee had some spiritual experiences and then he decided to bring his whole family on board of Guru Sahib's ship i.e. get his whole family to chhak amrit. Bau jee had been given amrit when he joined military. In those days, amrit was mandatory for Sikhs in military.
(Bau Mal Singh jee and Pooran jee)
Bau jee brought his family to Amrit Samagam organized by Panch Khalsa Diwan Bhasaur. During their stay there, Bau jee got up at amritvela and sat in a corner and started japping Naam. He had been japping Naam for few moments only when he felt that someone had taken him in an embrace. When he opened his eyes, he saw that a Singh with manmohni soorat had taken him in embrace. This Singh was Bhai Sahib Randhir Singh jee. Bhai Sahib said to Bau jee, where he had been hiding for so long and that Bhai Sahib had been looking for him. Bau jee did not understand what Bhai Sahib said but Bhai Sahib had recognized his companion from previous lives. Bhai Sahib gave immense love to Bau jee. Before long, Bhai Sahib and Bau jee became so close that it seemed they had known each other forever.
(Bhai Sahib Randhir Singh jee and Bau Mal Singh jee)
Bhai Sahib asked him the purpose of his visit and when he found out that he had come for amrit chhak his family, he said to Babu Teja Singh Bhasaur the organizer of the samagam, "look at this Singh Babu jee. Look how chardi kala he is. We are going to take him along with us to Narangwal and find Brahmgyani Jyot Vigaasi Punj Pyaare for him and his family". Saying this, Bhai Sahib brough Bau jee and his family to Narangwal and this way did not let his family chhak amrit at Panch Khalsa Diwan Samagam. There an amrit sinchaar was organized for Bau jee in which Jyot Vigaasi Singhs did sewa. From that day on, Bau jee became an integral part of the jatha. So much so that Bau jee did all the administrative work of Jatha. Whenever he was present he always did ardaas and for 65 years he did sewa in Punj Pyaare and enabled thousands to connect with Guru Sahib.
(Hazoor Sahib Yatra: Bhai Sahib Randhir Singh jee, Bau Mal Singh jee and other Gursikhs)
When Bhai Sahib went to jail, Bau jee took care of Bhai Sahib's family. After Bhai Sahib came out of jail, the responsibility of getting Bhai Sahib's kids married was given to Bau jee. All family affairs of Bhai Sahib were taken care of by Bau jee. Bau jee did a lot of sewa of Bhai Sahib and other Singhs.
Before going to jail, Bau jee was stationed at Ambala Cant. and Bhai Sahib used to visit Bau jee there. Once Bhai Sahib and other Singhs with him felt strong urge to go to somewhere. They went to the train station and when the ticket clerk asked where they wanted to go, they did not know where they were going. Bhai Sahib asked the clerk to close his eyes and repeat the mool mantra and pick a random ticket for them. The clerk oblidged and the ticket that came was of Ambala city. Bhai Sahib and other Singhs knew immediately that it was Bau jee who was calling them. Singhs reached Bau jee but just the next day, Bhai Sahib started planning to go back. Singhs were getting ready to leave but Bau jee got into great bairaag. Bhai Sahib writes that he will never forget the scene when they went to the water well and saw Bau jee pulling water from it. Bau jee was in full bairaag. Seeing Bhai Sahib he went to even greater bairaag and then he lay down on floor. Lying on the kacha floor, he started singing "Meri khalon Maujde Gursikh handaandhe". All singhs got bairaag and started doing kirtan. Bhai Sahib changed his plan of leaving early and did a Siri Akhand Paath Sahib there. This is when the great spiritual miracle of transforming the atheist Bhai Harbachan Singh to Jyot Vigaasi Bhai Harbachan Singh took place.
Bau jee was a very good Singh of Bhai Sahib's times and as the matter of fact he is the only Singh whom Bhai Sahib lavished with praise in his books, before his Akal Chalaana. Otherwise it was the policy of Bhai Sahib not to write about any Singh who was alive. All 23 Mahapurakhs of Ranglay Sajjan book had passed away before Bhai Sahib wrote about them.
It would be good if other Gursikhs could add stories and saakhis of Bau Mal Singh jee. There are many, that many Gursikhs know. Please post for the benefit of others.