Being friends with you shows that she doesn't reject everything. She can create some opportunities for him to get in touch with the society more, introduce your friends or relatives to him, and find more people to associate with her sincerely. Take her to do something with you and other friends, or travel together or something.

The army is no more ideal than this society. Without the care of his friends, he may be more closed alone. If she comes into contact with the dark side of the army alone, it may be her lifelong injury.

Of course, if someone in the army can really give her family-like help and care, that is another matter.

Generally closed personality, it is more difficult to change by yourself. It must be driven by external forces.