When he returned from several weeks in the hospital, he wanted his bed next to the window, where he could see his beloved rosebush.

【答】在return from 之后，一般接“地点或者事件”的名词，按说是不能接时间的。例如：return from 后面接事件：

Mr. Zhang has just returned from his trip abroad. 

张先生刚从国外访问回来。

I returned from work to find the house empty. 

我下班回来，发现屋里空无一人。

但是本句，several weeks in the hospital是一个整体“意群”，不可分割。不能去掉in the hospital，只说returned from several weeks。

“几个周 + 在医院里”，实际意味着“数周的住院”，相当于一个名词性质：a stay of several weeks in the hospital。中心词实际是“住院”，不是“数星期”。所以，本句表达正确。