You should share your class notes with him. Explain those chapters to him in which he would be absent. Be his best friend and always help him. Always motivate him so that he will not feel alone. Do practice of the hard subjects with him. This will benefit both of you.
May be this will help!!
plzzzz mark it as brainliest!!
I will talk to my friend and her parents to inform about the health problem she has to her teacher.then I will talk to the teacher personally about my friend's health problem which is a reason for her frequent absence in class which leads to her poor performance in class. I will ask the teacher to support her. I will tell that she hasn't spoken of her health problems because of her shy nature.

pls mark as brainliest
i will help her out in studies and clear her doubts