The charges carry a minimum term of 10 years behind bars. But now his 93-year-old grandfather has written a letter of support asking for leniency, saying he hopes to see him turn around his life "before I die."
Douglas was arrested July 28, 2009, at the Hotel Gansevoort as part of a Drug Enforcement Administration probe.
Cameron is the son of Academy Award winner Michael Douglas.
The Associated Press contributed to this story.
