Haven’t used this yet, but khan Academy has various video lessons, math is the most popular. There is an app for it as well and a website where your child can sign in and track specific courses. I am not sure what world view is used for the videos besides math, they might teach something controversial to you, just research beforehand.
EasyPeasy Homeschool has curriculum meant for the child to somewhat self educate with instructions or links for each day’s lessons for each subject. Perhaps you could pick one subject of interest to your boys to do from the EasyPeasy website while you are working with the other.
Duo lingo app for learning a foreign language, only thing is the type written requirement part of the program may be a barrier to using it independently for an 8 yo, but it might be fine.
How stuff works, selected National Geographic Documentaries, and travel shows.