A Secret Service agent in his security group has a two-year-old son who is losing his hair as a side-effect of treatment for the cancer.
The 89-year-old former president shaved his head earlier this week at his summer home in Kennebunkport, Maine, after he saw members of his security team with newly shaved heads to show support for the 2-year-old son of the agent.
The boy has been identified as Patrick. Bush security group has launched a website, www.patrickspals.org, to help with expenses associated with Patrick's treatment. The former president has also made a donation for the treatment of the boy.
Bush senior himself was in hospital earlier this year for two months because of a bronchitis-related cough.
He was the 41st US president, and served one term in office, from 1989-1993.
George and Barbara Bush had lost their second child, 4-year-old Robin Bush, to leukemia almost 60 years ago.