Please Help: How can I shun my brother's Friend Advances?

My Brother's friend has a romantic feelings for me and is not taking the hints that i do not share his feelings, how do i put a stop to this?



We are both 19 and he has always look up to me for advice and support, since we did the same combinations of A/level subjects,  which I now believe his taking this as a lucky chance to be close to me. 

I recently discovered he has said things about me to other friends of his which are totally inappropriate, and now he's asking my Brother to ask my Mum to allow him to stay in our house for a week because his Parents are going out of Town for Prayer meeting. I don't want our friendship to be ruined because of his feelings towards me but I want him to realise he's wasting his time.

Thank you for reading my plea, while I wait eagerly for your advice.