Although I admire Jay chou too,my life is more important to me than his is. 為甚麼his後面還要接is,不是直接用his就好嗎?

... my life is more important to me than his (life) is.
這裡的life省略。若將is也省略，也是正確的，因為不會妨礙我們理解原句意。
my life is important to me
his life is important to me
是這兩者在做important的比較：more ... than。

原句：Although I admire Jay chou too, my life is more important to me than his life is important to me. (雖然我也很欣賞周杰倫，但我的生活對我來說比他的生活對我來說更重要。)
(原句省略為) 本題：Although I admire Jay chou too, my life is more important to me than "his(所有格) life is." →再省略→ "his(所有格代名詞} is."
# (本題)若無"is"，那麼"his."的意旨就不明確，而若"his(所有格) is."是不符合文法的；而且，加"is"的 "his( = his life) is." 更明確了被省略的字詞。

Amendment: Although I admire Jay Chou's noble behaviour and yet mine being better than him. Yip

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