Who are we to judge? There is no God, just humanism and under humanistic theory, no person is in a position to judge another. Maybe the mother and boyfriend suffered a trauma earlier in their lives which would excuse torturing and abusing the kids.
I mean, it's not like they denied puberty blockers to the boys. Now THAT would merit criminal prosecution!
Consecutive sentences, don't even entertain concurrent ones. Gen pop (a little jailhouse justice). Seize the property and use the funds for the long-term care these kids will surely require. No mercy. These people should suffer what the kids suffered, x 100.