(Apologies for the length, this got a little out of hand as I was writing it.)

A little background to start; I'm 16 (nearly 17), I have a 20 year old sister who is my best friend and an amazing Mum (38). My dad (50) left my Mum not long after I was born and got married about 5 years ago to a horrible woman (48 I think) who had a son from another marriage (23).

Me and my Sis tolerate my dad for our Mum's sake. She's always been adamant that we all remain in each others lives, but we've managed to reduce to the bare minimum. I see him maybe a combined 3 or 4 days a year. Mostly over Christmas, sometimes for my bday or my Sister's or his. Luckily he lives like 300 miles away.

At one point I started to think that maybe I could like him, but then he got married to the horrible witch that is my step-mother. She is a cold, spiteful hag of a woman who at best shows us nothing but contempt and exudes, quiet seething hatred and at worst will make snide remarks about us and our mother to our face and try and sabotage what little relationship we have with our dad.

My step brother is her life. He takes priority in her life over everything and can do absolutely no wrong. When we stay at my Dad's we get some serious Harry Potter/Matilda style treatment. He gets the lion's share of food and drink, we're to blame for everything etc (this includes my Dad and I have no idea why he'd put up with it, not that he actually deserves any better) and being kids when we met, we obviously tried to be friends with him, but were quickly denied that chance by her helicoptering.

She's absolutely coddled him his entire life and has never let him out of her sight, as a result he has zero social skills and no friends. Her constantly telling him he can do no wrong has lead him to be about 5 years behind educationally. He's also a complete and utter cretin. Although (so far) ultimately harmless he's been a creepy perv towards me and my sister since I've known him. I've never caught him spying on us or anything, but he doesn't know how to hide his stares (or erections) when we're just in the same room as him.

So the actual problem is that he started university in my city last Sept/Oct. I can only assume he quickly alienated the other students in his halls and on his course, because about a month in I got a phone call from him (he must have got my number off my dad as I never gave it him). He wanted to meet and hangout and wanted to know if I could show him around the city. How my older sister, who also goes to his university, escaped this I don't know, but it was something she certainly teased me about.

I agreed and it was pretty painful (about as much as I expected). We met for a coffee and he barely spoke to me, just sat there awkwardly the entire time and one-word replied to everything I asked him. I showed him a few places that I thought he might find cool or interesting or useful, but I only lasted an hour before I couldn't stand it and made excuses to bail and that I'd made plans to meet friends (all ~16-20yrs old, mostly girls). He tagged along. I was trying my hardest not to be mean and he just didn't get the message that he was not wanted. He continued to barely say anything to me and nothing to anyone else and just awkwardly stand around near us and noticeably stare inappropriately.

I thought whatever and that I did my good deed and didn't have to do it again and put up with my friends teasing me over my creepy relative. Whenever he text I made excuses (real or not) and I didn't see him for a few weeks, that is until he started 'bumping' into me in town. Not just in the city centre, but my own home town centre too. At first I just thought it was a bad coincidence, but then I kind of realised, at least in the city centre, he was going to the coffee shop I liked, to where he followed me and my friends and that's where I was bumping into him. I even had reports from my friends that he was bumping into them when I wasn't there and trying to tag along and asking if I was going to be there.

This went on for like 6 months. Not always, but a lot of the time I went into the city centre, either during the day or at night, he would magically be there too. He was basically stalking me and my friends. I made a post on another sub asking for help (which I have since removed). I wanted to call him out on it, but I didn't want to essentially scare him into following me and waiting for me without me even knowing. I'd much rather he 'bump' into me and awkwardly stare at my tits than I would have him continue to stalk me without actually approaching me. (I'll add that I don't have a huge social media presence, everything I do have is private, I not friends with him on anything and only add full profiles of people I know or at least have met/am acquainted with and I don't geo-tag anything).

The overwhelming advice was to call him out and tell him to fuck off. Well I did and guess what? He just started following me from the shadows instead, exactly as I thought he would. I caught him and shouted at him about 3 times before he eventually stopped (or more worryingly, got better at it). Luckily for a lot of this year I've been preparing, studying for and taking my GCSEs (which I aced), so I've not nearly been as sociable or going out as much and when I have it's mostly just been to friends house to chill out.

Obviously my GCSEs have been over for a while though and I've been on my summer holidays before going to sixth form next month. At first I didn't see him and neither did any of my friends. But this week he approached me once and I caught him following me once. I'm seriously on the verge of going to the police over this and I'm 100% going to threaten him with the police. At first I was thinking that'd be harsh, because he's probably just got social developmental issues, either naturally occurring or because of how his mother has raised him, but I can't not go out. I'm going out drinking with my Sister and some mutual friends tonight to celebrate my/our results and I'm absolutely dreading him either trying to tagalong or catching him following us (luckily my Sister's very large and fit BF will be with us). I'm at the point where I just don't care anymore, if it ruins his life, his mother's or ends my and my Sister's relationship with my dad.

I don't really know what I expected when I started writing this. It's mostly just for my own sanity I think, as it's stuff I've basically bottled since Christmas as I've had more important things going on with school. It's mostly just ranty, as I'm pretty settled on what to do, but any advice is also welcome.