It’s quite possible that the manifold was cracked when your wife drove into deep water, that’s not unusual. It should be able to be welded, but you need to remove it and inspect it to know for sure.
Ford Motor Company (Ford) is recalling certain 2016-2019 Lincoln MKC, 2016-2023 Explorer, 2019-2020 Fusion, 2019-2024 Ranger, 2020-2022 Lincoln Corsair, Escape, 2021-2024 Bronco, Bronco Sport, and ...