During apartheid, Coleman was a founding member of the Detainees' Parents' Support Committee, a civil society organisation, after his son was detained for his political activities.
[1] His eldest son, Keith, was detained without trial for his activism in October 1981 alongside Neil Aggett and others who appeared on a list of anti-apartheid "comrades" written by Barbara Hogan and intercepted by the police's Security Branch.
Keith was held at John Vorster Square in Johannesburg until April 1982,[1] and during that time Coleman, according to his other son, took up a daily vigil outside the police station, holding up a placard to protest political detentions.
[3] Also during that period, Coleman, his wife, David Webster, and others founded a committee, initially meeting at Wits University, for the parents of the young activists who had been detained in the October 1981 raids.
[1] The committee became a national organisation for legal and financial assistance, petitioning, and record-keeping in advocacy for detained anti-apartheid activists and their families, growing especially quickly during the 1985 state of emergency;[4][5] it established headquarters in Khotso House in Johannesburg.
In November 2021, President Cyril Ramaphosa awarded Coleman the Order of Luthuli in silver "for his contribution to the fight for liberation and promotion of human rights through active involvement in lobbying utilising both civic organisations and government institutions".