Barrett and 13 others, including former Canadian prime minister Kim Campbell, were named to the order last week, with investiture set for early September at Government House in Victoria.
But New Democrat MLA Maureen Karagiannis (cara-gee-ANN'-iss) says the former premier is in declining health and is now in a residential care home.
She would not comment on the illness Barrett is suffering, but says the 82-year-old is enjoying his privacy and his family hasn't yet decided if his health will allow him to attend the upcoming ceremony in person.
Barrett was first elected MLA in 1960, holding his seat through 1969, when he won the leadership of the provincial New Democrats, leading the party to a single term in office from 1972 to 1975.
Barrett's government is credited with several enduring pieces of legislation, including creation of the Agricultural Land Reserve and the Insurance Corporation of B.C. (CHNL)