Checking on the validity of "to charge" as a correct fit for "to claim", "to assert" in some previous OP, I came across the expression "in charge of" pointed up by the Collins dictionary -- besides its shared meaning [having responsibility for] -- as an Americanism for "under the care of".
34. In charge of: a. Having responsibility for -- b. US: under the care of
Collins English Dictionary, complete and unabridged, Ed. 2003
The funny thing to it is both meanings of "in charge of" obviously go in opposite directions, to such an extent that -- with an unclear or unspecified context -- saying "The old lady was in charge of her grandchildren" could mean that the old lady had responsibility for her grandchildren (for instance, because both parents are dead), but also just about the contrary, i.e the old lady was under the care of her grandchilden (both parents are dead and the old lady [their gramdmother] suffers from severe Alzheimer's).
Which of those meanings of "in charge of" is actually more common to modern day AmE?
Parents can safely leave their children in charge of the babysitter. source