"Can one wait when one is hungry?" That, in the first place, it is very rare for any one to die of hunger, literally...
Yes, Valjean, but as you demonstrated... you don't think clearly when you're that low!
... fortunately or unfortunately, man is so constituted that he can suffer long and much, both morally and physically, without dying;
This is something we've talked about in H&G. The will to live is extremely strong even if we don't think it is.
It's sad. Through that chapter you can just read his heart slowly growing cold.
When the heart is dry, the eye is dry. On his departure from the galleys it had been nineteen years since he had shed a tear.