Question: What do I do if a friend of family member with an anxiety disorder resists being evaluated and diagnosed?
Answer: It's very difficult to use a strategy where you're attempting to force somebody into treatment. The best you can do is to express your concern, perhaps support that expression of a concern with observations that you've made about the person and the difficulties that they're having. And then do your best to supportively encourage them to seek out assistance.
Typically people are more comfortable talking about these kinds of issues with their primary care doctor and that might be a good place to start. However, if an individual is willing to go see a mental health professional then that too would be a very reasonable approach.