Appropriate Coaching Clients

I’m a psychotherapist in private practice and have just started the coaching certification program. Very excited about changing directions at this point in my career. Trying to better understand when coaching is or is not appropriate for someone that may call with a history of a mental health disorder. Are there screening questions a coach would use to determine if a potential client is well-suited to work based on the Model? I know some mental health practitioners capitalize on their training and expertise in mental health to create their niche but I’m hoping to better understand how to best screen potential clients in the future who present that may be seeing a mental health practitioner as well. In mental health, we do not take on a new client if they are already seeing another psychotherapist. Hope to better understand this. Thanks in advance for your thoughts/suggestions.