I hate laws in general but I have no idea why a parent can't demand ISP provide G rated internet. You'd think a company could make a bundle on providing internet filtered.
There is a section in dns for edit hosts.
I cut and paste the 0.0.0.0 lines and apply. Usually apply in small sets as the entire thing might cause the router to croak.
openwrt doesn't like any comments like #. If you get a hosts file or set you need to fix it.
I have to warn you that some of them are too large for some routers.
I just tried multiple aliases on a single line and it works but limit is maybe 256 charactors.
I had to go in and use vi editor to reduce my list to under 8000 lines. I guess i could try the single line edit on last line to see. The bad lines show up in red even.