Using a sectional map would have prevented this, they indicate what altitude is required to clear terrain. It is required to have a current sectional on board. If he was flying VFR he sould have not been in the clouds. And if he inadvertently flew into clouds a simple 180 turn gets him out. Bet also he was not communicating with Seattle center. Tragic, should never have happened.
The problem with a VFR chart is that it doesn't give you your present position. If you're off course you could think that you have enough altitude to clear any obstructions. With even an iPad you would know exactly where you're at and with synthetic vision you'd know if you have enough altitude.
I see the same thing with my Jeep club. People with charts debate where the group is at. With my iPad and topo app I know exactly where we're at.