That's such a good point.
They have repeatedly stated that the lomg walks have helped Moth's condition - well if it can be proven they never even did any long walks, that's pretty damning too.
On top of that, they haven't even really proven Moth's diagnosis was when they said it was.
So potentially they've not only lied about the timeline/diagnosis but then lied about what 'helped'.
The whole thing becomes fiction.