My Family Tree

Canadian parliamentary guide 1935:
Allen - LUCAS R., (5th Prince). B. July 17, 1878 at St. Nicholas, P.E.I. S. of Benj. C. Allen, and Melvina Goodwin, his wife, both born in N.B. and went to P.E.I. in 1870. Ed. at St. Nicholas and Summerside, P.E.I. M. June 16, 1903, to Winnifred, dau. of J. A. Brace, of Summerside. Five children: Irene, Florence, Edith, Mildred, Margaret. Pres. Brace McKay & Co. Ltd.; Dir. Pure Can. Silver Black Fox Co.; Pres. Summerside Bd. of Trade, 1922;etc.

Wikipedia and PEI Parliamentary Handbook:
He worked as a delivery person for Brace, McKay and Company, later becoming manager of the grocery department and then company president. In 1926 Allen became president of Brace, McKay and Company, a position he held until 1939 when he became vice-president and took on reduced duties. He remained as vice-president until 1958. He was also plant manager for Island Foods Inc., which manufactured dehydrated potatoes for troops during World War II.
Allen served on the boards of directors of a number of Prince Edward Island companies, including Brace, McKay and Company.
He also served on the town council for Summerside and was president of the Summerside Board of Trade.
He served in the province's Executive Council as a minister without portfolio. Allen died in Summerside at the age of 85.

Allen, a Liberal, was first elected to the Legislative Assembly in the general election of 1927 for 5 Prince. He was re-elected in the general elections of 1931 and in 1935. He was appointed as a Minister without Portfolio in August 1935. He was awarded the King's Jubilee Medal in 1935. Lucas Allen died 7 April 1964.

Winnifred Allen was the daughter of John A. Brace from Summerside and Margaret Howatt from Tryon.
References:
some web bios have a photo; see new website from PEI Legislature
CPC 1928; Maritime Reference Book 1926 pp. 63-6-1, 410, WWC 1936
II p. 3; Guardian 9 May 1938, 8 April 1964; Journal-Pioneer 8 April
1964; PARO: RG 19: Vital Statistics series 3; Marriage Records
subsencs 4; Marriage licenses.

Lucas' obit was in the Journal Pioneer 8 April 1964, page 3, column 5 "L. R. Allen, Prominent Businessman Dies". It listed his daughters as:
"Irene (Mrs. Dr. Lachlan MacPherson), Hampton Station, N.B.; Florence (Mrs. Fraser Ross), Halifax, N.S.; Edith (Mrs. Manning Archibald), Montreal; and Margaret (Mrs. Allan McColl), Mount Royal. His wife predeceased him in 1962, and another daughter, Mildred (Mrs. D. F. Archibald) died in 1960." (from PEI Ancestry)