It is questionable whether the death of such a physically frail person is good subject for open gloating - but each to his own. Sheikh Yassin himself would not be upset. From his point of view, he has attained that status he sought for years - he is a martyr. Preferable, maybe, to living on locked in his paralysed body during a final period of decay.
Anyway:
He has awakened from the dream of life
Tis, we who lost in stormy visions, keep
With phantoms an unprofitable strife ... (Shelley)