Could he have succumbed to his injuries?

succumbed 是动词 succumb 的过去分词形式。succumb 由前缀 suc-（表示"向下"）和词根 -cumb（来自拉丁语"躺下"）组成，本义是"屈服、屈从"，引申为"因...而死亡"。succumbed to injuries 表示"因伤势过重而死亡"。