编辑下列句子中的语法错误并解释为什么它是错误的："我和他在去年的这个时候买了一只小狗和照顾它变成了我们日常生活中令人愉悦的一部分。"
我和他在去年的这个时候买了一只小狗和照顾它变成了我们日常生活中令人愉悦的一部分。
"I and he" should be corrected to "he and I" as the correct grammatical order is to list oneself last when referring to oneself alongside others. 

Corrected sentence: "He and I bought a puppy this time last year, and taking care of it has become a delightful part of our daily lives."