What does it mean to take a bath in a broken house?

"Bathing in a broken house" is an allusion from "Biography of Heather Fan Town".

This allusion describes that when Fan Zhen was a prefect of Yidu in Longchang, Nanqi, he built his own hut because the house was dilapidated and could not shelter from the wind and rain. This cabin is very simple. The roof is paved with thatch and the walls are surrounded by bamboo fences. After the completion of the thatched cottage, Fan Zhen invited Wang Xiuren, then the prefect of Yidu, to bathe in the "broken house".

"Bathing in a shabby house" means that you live in a humble house, but you don't mind inviting others to a party, which shows that you are open-minded, don't care, free and easy, and don't stick to material life.