Freddy Mercury is either visiting you in spirit or not. Thus, your image or vision is either real or a hallucination/delusion. There are people who claim to see spirits but it’s never been proven scientifically as to whether this phenomenon is real. If your vision is not real, then it would mean that you’re experiencing a hallucination or delusion. Hallucinations and delusions are associated with specific mental health disorders.
Children often have imaginary friends because they have great imaginations. Parents tend not to worry because eventually the imaginary friends go away. It is rare, though not unheard of, for an adult to have an imaginary friend. You did not detail your conversations with Freddie Mercury. Without similar information, it would be difficult to determine what may be happening.
It would be advantageous to be evaluated by a mental health professional to determine if what you are experiencing is a symptom of a mental health disorder. You perceive this “imaginary friend” as being healthy but if it is not real, then it’s unhealthy.
When speaking and interacting with a mental health professional, he or she might identify other symptoms that the untrained individual might not perceive as being symptoms. There may be symptoms that you don’t perceive as being problematic but ones that a mental health professional would identify as such.
I hope you will consider my suggestion regarding an evaluation by a mental health professional. If your mental health is being compromised by a psychological disorder, then treatment is imperative. Even though you perceive this phenomenon to be healthy, if it is not real, then it can be psychologically damaging. Hallucinations and delusions, if left untreated, can become worse over time and can significantly degrade your life. Please take care.