His friend saved him from financial crisis by bailing him out.

bailing 是动词 bail 的现在分词形式。bail 本意是"保释"，引申为"帮助摆脱困境"。 bail out 是一个短语动词，意思是"帮助某人摆脱财务困境"，通常指提供经济援助来解救对方。