I do have doubts - stuff like that would be under NDA.
You said you were from ireland, and coincidentally there is the facebook headquarters there . Maybe you could have made up you were in Ireland too . https://www.quora.com/Why-have-Google-and-Facebook-chosen-Dublin-for-their-European-headquarters
You do look like you are trying to build up a reputation on Steemit, so basically if it doesn't happen , people will probably not like it if you 'lied' that your sister works at facebook and said this.
The other thing that would motivate you is that you put the most money that you have right now into reddcoin... so you are trying to get other people to pump up the price.
I dont know, Its not every day you get inside tips that actually follow through, but its your reputation on the line.