One thing that can add immeasurably to the feelings of despondency of those who are sick and suffering is the sense that their pain is futile. What our faith has to offer to the sick is a sense of purpose, to see that whatever they endure is not in vain, and, in fact, can be of great value; salvific value even.
The world sees pain as pointless - I suppose that if you limit your horizons to believing that this life is the be-all-and-end-all, then pain is the futile cousin and pre-cursor to the absurdity of death and annihilation. For us Christians on the other hand, pain is full of potential - we know that the sufferings of Christ were the very means of our salvation, we know too that when united to the sufferings of Christ the pains that we experience also take on supernatural value and can help to atone for sins and to win graces from the good God. How consoling it can be to encourage a suffering soul by telling him that what he is undergoing can bring comfort to the souls in Purgatory, or help some other soul to be saved - it means, then, that suffering becomes something immensely positive in so far as we accept it in faith.
We should remind those who are sick of the great contribution they have to offer to the salvation of souls, and encourage them in their privileged vocation of sharing the burden of our Lord's own suffering for the sins of the world. Whilst in charity we do what is necessary to alleviate the pains of the suffering our view is wholly different from that of the world - we see that the suffering, the disabled, and so on, have something tremendous and beautiful to offer mankind.