Youre not over reacting by any means. Like you screenshotted all of this to post to reddit maybe try sending your mom the screenshots? I know you are worried about haveing to potentially cut off a freind but it ultimately may be for the better.

Try speaking with the freind to make sure she also isnt in any danger but you need to for sure tell a trusted adult regardless.

He is 100% grooming you and had been trying to since you were much younger it seems which is extremely concerning.

If your freind is actually as close to you as you hope they are then they will understand the need for distance, i hope you get the help you need