He can't and I really feel sorry for the guy.
He's essentially trying to save a tree diseased at the roots by poking at the limbs. But when somebody comes along and suggests that he should consider looking underground, he spits at them and throws a blanket over the tree to prevent anybody else from seeing it for the time being. As soon as the vicinity clears, he pulls down that blanket and begins poking at the branches until the next guy comes along and it happens all over again.
It's both sad and amusing, which leaves me undecided between whether I should laugh at him or pity him.