no he's not using too much back and he's at least parallel on every rep, he's not rock bottom but he's at least parallel.
You might be right, I could be mistaken on the depth but it looks like he's a hair above parallel. Not bad at all. Better form than you see from 95% of gym rats.
I saw a bit of back rounding toward the end. Again, not a lot, but it's good to be aware of even the tiniest margins for error because one sloppy set of heavy squats can kill your back forever.
But again, sevastase, good job.