I agree Jane is trying to send out as much comfort and sympathy and strength (also) as she can in her letters. She is uniquely qualified to do so. She is able to express so much in her writing. Jane praises Cassandra for her strength, “for the present I dare say you are equal to everything” and I think she wanted to comfort others more than be comforted herself. She wanted to be useful and foresees Henry will do the same: “Of Henry's anguish I think with grief and solicitude; but he will exert himself to be of use and comfort”. Writing letters to announce the sad news, “We will write as you desire, and I shall add Bookham…”, cannot be easy or pleasant but is useful indeed because, I think, it is an emotional and draining task. In writing Jane relieves others of the burden. I think also that Jane may feel comforted in doing all she can to help. I think characters like Elinor Dashwood are so believable because they are a product of Jane’s experiences. (:D)