Now, I know the blind man is supposed to be Grantaire and the Light is Enjolras, Hugo has weaved enough light/darkness symbolism into his hell hole of a novel for that to be clear

but consider

Enjolras keeps dismissing Grantaire. All the time. He never realises the extent of Grantaire’s feelings and faith for him. Not until the very dusk of his life, when darkness is closing in around him, when Grantaire manages to make him smile.

Then, truly, no one loves the light like the blind man