So far as donating miles goes....

You may mean well, but you are really only helping the airlines. They burn liabilities, while giving away seats that cost them nothing as they otherwise would have been empty.

Why don't I see sick kids filling the empty seats on airplanes? If the airlines cared, they'd let people in need go standby for free at anytime. Give the airlines my miles? Very funny. It costs them about $5 to let those people on the plane. They don't need my or your miles.

My advice, save your miles for a time when you or a family member or friend need them. Bereavement fares are often higher than unrestricted coach. That's when miles are really worth their weight in gold.