"The sitter observed inconsistencies the furnishing of my oldest son’s room and observed the smell of urine."
"The inconsistency wouldn't be evidence of the kid being tied down, would it?"
"If that were the case, would the families of his home school group be showing up in support of the parents? Would Help One Child send a representative? They did, twice."
Since you haven't told us what those inconsistencies are, how can we assume that other families showing up for support know what they are?
Possibly the room was bare of ornamentation and furnishings. Absolutely reasonable with a child who has destructive rages and tantrums.