Diagnosis request from boss possible?

Due to sensory issues and repeating situations with a bully at work I was forced by the situation to disclose that I’m autistic. I spoke to my manager. I told him the truth - I don’t have official diagnosis, but I was informed by my psychiatrist and therapist that I have Asperger and I was examined by neurologists who confirmed I’m very sensitive (that was long time ago). To my surprise my manager listened to me with understanding without any comments such as “you don’t look autistic” etc. and spoke to the guy who makes fun out of scaring me out with sudden explosive sounds like horn for example. He didn’t request any documents or anything, he told me that he noticed this issue with me. So I’m allowed to wear ear plugs in the office without problems he even said that it’s so good Im solution oriented. I find it really good that my manager is willing to solve my issues but I’m also concerned.

• What if they request an official diagnosis from me? It’s complicated and expensive.
• Also I’m worried about some gossips in the company and more bullies. I really like and enjoy this work and I feel that my colleagues also like me. My manager told me I don’t need to worry, I’m doing really well at work and I’m kind to others and hard working. The bully himself is so disorganised but  i do my best to help him organise some things when we work together instead of making fun of him. I hope he will not make fun of me anymore since he already knows I’m an aspie.