How do you say this to a manipulative person?

I was in the talking stage with someone who turned out to be extremely manipulative.

I want to tell him that he’s coming off as manipulative and I can’t help him with that bc I’m not a therapist.

I’m a v blunt person and I don’t think that my choice of words in the above statement is v good. It sounds aggressive and I don’t want to sound like that.

I basically want to tell him that he’s manipulative and should go for therapy. What would be a better way to say this?