How to say “He lathers his whole head with bar soap because he refuses to buy shampoo.” in Japanese

In Japanese

うちの兄(あに)、シャンプーを買(か)いたくないからって、固形石(こけいせっ)けんを泡立(あわだ)てて頭(あたま)まで洗(あら)ってるの。

Uchi no ani, shanpū o kaitakunai kara tte, kokei sekken o awadatete atama made aratteru no.