Those videos appear to be backed by good science, I say that as someone who enjoys a good burger. But... as someone who has watched all four of my meat/potatoes/processed food loving Grandparents grow old, and spent many hours in hospitals an emergency rooms with them, I'm seriously thinking about giving up animal products for the sake of my Grandkids if not myself. Your daughter might be able to whip that vegan, but that vegan will probably never be overweight, get cancer, or other diet/lifestyle related diseases (hopefully your daughter doesn't either regardless of diet). And if he wanted to be more muscular, I'm sure he could start lifting weights and drinking
vegan protein powder. The bottom line as I see it is that a hamburger, like a lot of things that taste good, is not great for us whether grass-fed beef or some sort of vegan copy.