You are dealing with a "I need my mommy to help me with my life" and a mother who is "My purpose in life is to be his mommy" and there is not going to be any room for you in that picture, which is what they are saying by their behaviors. They have become each others "significant other" and you can't "change" that, they are not even interested in you changing that either.

You don't even need to know if there is "intimacy" involved, what you have seen already is enough to let you know it's unhealthy and you should step away from this "dyfunction" completely.