The US Flag Code states the flag shall be flown at half-staff for ten days for a sitting Vice-President, but not a former one (unlike the rule for Presidents, where the flag is placed at half-staff for thirty days for either a sitting or former President).

The rule for a former vice-president can be modified by the President or a governor (or mayors in states where the state legislature has given a city council that authority). Gov. Tim Walz of Minnesota has not ordered the flags in that state to half-staff as of yet.

Minnesota State Government Half-Staff Notification Page