His plans worked in the long run
He wanted to help her get out of depression because of her toxic past relationship and, in the process, fell in love with her, and one of his reasons was that she helped him get out of his social anxiety. Because of this, he could not allow her to suffer. He proposed, and she said no, and it was not just a no- it affected their friendship because she went off-grid and out of his reach. She stayed alone for some time.
As fate would have it, they connected again, and he was curious to know her mental health status while they were apart. He learned that she had been locking herself in the room all that time and remained incommunicado for a while. He insisted that he loved her and kept helping her until she started becoming normal with time. He proposed again, and she accepted, and they are four years in the relationship and love each other deeply.