It seems that Lou truly loves Will in the novel "Me Before You," more so than he cares for himself. Early in the events of the book, Lou learns of Will's desire to commit assisted suicide, and of his pact with his mother to live for another six months.
Lou attempts, from then on, to encourage Will and help him learn to love his life in spite of his disability and confinement. Her actions throughout the story to improve his standard of living and give him reason to continue persevering in spite of his dissatisfaction with his life show that she deeply cares for him. In the end, she shows how much she disapproves of his decision to end his life, hoping to convince him one final time not to do so. While he may be in pain and hates his life, she still tries to convince him to go on, and this, in my opinion, shows how much she does love him.