Secondhand serenade - Let it Roll strum pattern?

Alright so, I'm not a big fan of this band, but I was asked to make a vid playing this song, and tbh I can't figure out the strum pattern to it, my guess on it from listening to the song was nothing but downstrokes. I got the tabs and the right tuning to it, so no problems there.

I looked up videos of others playing this song, but all i found was things that didn't sound close whatsoever, or nothing but downstrokes throughout the chords. So yeah, if anyone knows the strum pattern to this song 100% correctly, I'd be happy if you shared.