Dear Ken,
I am so sorry to hear that you are ill. I write the letter to know if you feel better now.
First, you needn't worry about lessons. I will help you to follow all lessons. And I can lend my notebooks to you. I believe you can solve these problems easily because you are so smart. Then you should keep a optimistic attitude to the situation now. Because having a better emotion benefits to your recovery. In school I will finish these things for you. Everything is ok and you needn't care about anything. There is only task for you to let become healthy.
If I have time, I will go to see you in your home. Hope you can beat the illness fast and back to study with us.
Yours sincerely,
Li Ming