It's been a while, they should run into each other again! Levi is also very "the living over the dead" while still being as respectful as possible in a Situation, so he'd absolutely get supplies off corpses that they don't need anymore.

Alternatively he's probably getting horse'd into the water (look, he likes horses, he used to have one!) and could need some help, though with both of them unable to swim it could be tricky... but there's always ropes, logs, and whatever else for cold water rescues :')