1、lost不是动词原形,不能再加s.
2、Baudelaire前的定冠词the表示：他是Baudelaire and Walter Benjamin笔下的唯一人物,这是错误的.结尾处的the crowds也是同样问题.
3、working 应为 walking.
其他语法没有错误,但意思表达的不够清楚,建议改成：
He is just like a prodigal in a Baudelaire and Walter Benjamin's novel, drifting through life, losing himself, and walking through crowds with a camera.