
It definitely qualifies as really old. It is a Roman bronze coin from the 320s AD, of "camp gate" type, under Constantine the Great or one of his sons. It is too worn to say which of those emperors or which mint, but here are some examples of a Constantine the Great coin of this type: https://numismatics.org/ocre/id/ric....295?lang=en
Its condition is too worn for it to have any value, but if your mother in law picked it up in her bank, that is quite fascinating! Finding Roman coins in circulation in today's US must be completely extraordinary
