What can I do for someone that is depressed and refusing to get help?

Caring for someone. It's nice of you to want to help. But, you cannot change or be responsible for someone's mood/health. The best thing you can do is to take good care of yourself and your own well-being. Beyond that, inviting this person to participate in projects, social gatherings, walks, etc. Might help. If suicide risk becomes a real concern, call 9-1-1, or a crisis line for immediate assistance.