Yes, it is possible. Some charities like Make A Wish will give you the dates when they could use a room and the you simply book it in the names of the traveling party. Other times folks have offered points available for raffle / auction thru a charitable organization. In a situation like that, you would set the terms (i.e. Sunday thru Thursday at Animal Kingdom Villas in Adventure or Choice season, booked subject to availability.)
Just be aware that the IRS prohibits any tax deduction of these timeshare uses as a charitable donation. I'm sure the organizations would welcome the gesture, but it won't save you any money with Uncle Sam.
Due to the tax implications (or lack thereof), I've seen people suggest that you instead rent the points and make a cash donation with the proceeds. That seems like a logical alternative.