Don M. Rajapaksa was a Ceylonese politician. He was a member of State Council of Ceylon and the Senate of Ceylon.
His sons were George Rajapaksa the Government Minister and Lakshman Rajapaksa the Member of Parliament. His brother was D. A. Rajapaksa and his nephew is former President Mahinda Rajapaksa.
References
D. M. Rajapaksa Wikipedia(Text) CC BY-SA