Firstly, beautiful flying video, one of the best I've seen. Totally legal? I doubt it.
He said it was "clear" at Yosemite, but when he got there, it really wasn't, but the urge to complete the mission was too great because once he got there, it was stunningly scenic, as in: "Oh, man - can't pass up seeing this!" He could've waited a few days for the clouds to clear after the storm. The snow would've still been there.
Yes, he got too close to clouds and the ground on several occasions. Probably illegal, by the book.
Was his daughter scared $h!tless? Noooo, she wasn't. She sounded like an inexperienced passenger when it comes to anything other than straight n' level flight on a CAVU day. I heard some nervousness, but nothing close to terror or panic. I've heard the same tone from my kids and wife if I barely strayed off the GPS heading or handed them the yoke for only a few seconds.
If I was him, I wouldn't post such videos on YouTube. I understand the desire to share such an experience, but it ain't a good idea.