No. You cannot claim your parent who had over $10K in gambling winnings----no matter how much they also lost. Sorry. The only income that does not "count" when you want to claim an adult dependent is Social Security. Your mom or dad had way more than the $4300 limit that was NOT SS. If they have a gambling problem, that is a whole other issue.
Further .... your parent may need to file a tax return with those winnings.
Who has to file?
http://www.irs.gov/uac/Do-I-Need-to-File-a-Tax-Return%3F