Serenity v0.8 by N2TheFire - Adult Sex Game

MC's mom got cancer when he was 15. She fought for 5 years and finally died. During this time, MC did nothing but care for his mom. Didn't meet girls or date, didn't make many friends. His only friend is a girl who practically grew up with him, and she's in love with him... but he has (so far) not accepted her advances. Meanwhile, he learns that his Mom wrote a book for him.