I have a question regarding rebar and concrete as it pertains to a concrete foundation slab?

photos look like hes doing ok. i would have wanted wider forms for a pour that thick . you want your edges square not angled back the way the 2x4 's and dirt will make your edges turn out. may be ok tho. he should have taken his base out past the pour a little to support the edges also...make sure he back fills it well...