Apartment deemed uninhabitable

(US-WA) the sprinklers in my partner’s apartment building malfunctioned on Sunday and flooded the two apartments next to him. He got hit a little bit and his floors and ceilings were wet. The apartment manager deemed his apartment uninhabitable and came in to put like 10 dehumidifiers around the apartment without notice. Now his apartment is like 90 degrees or more and the dehumidifiers are insanely loud 😭 On Sunday, they told him that they would waive the July rent if he got out by the 14th, but when he talked to them today, they were saying that they’d only prorate it after the date he got all his stuff out. Can we do anything about this? I’m pretty sure this is illegal, especially because it was their fault that his apartment is uninhabitable. We can’t be in it to move for more than like 20 minutes without feeling sick, and he has to pick up everything and move with zero notice. We both work, so we have to come every night this week to try to get stuff packed, which means the apartment has been baking in the heat all day. And the dehumidifiers are stupidly loud… we have to shout over them. I feel like giving back the July rent is the least they could do :( what steps can we take/what do we need to do to get compensated for his displacement?