DIY: build a little family from scratch

So, this is how the story goes. My grandma, now living with us, used to live in Alicante. She happened to refuse to sell her home when she moved in here with us, so there it is, empty. Alicante is where I want to do my Phd. Great plan: I move there with Eric so we don’t have to spend that much money on rent (my grandma wouldn’t charge us at all) and everybody is happy. Not really.
I have a cousin, flight attendant, who owns an appartment in Madrid and is waiting for her new house to be finished here in Valencia. Her boyfriend is unemployed. They’ve decided to move in together to my grandma’s house. I’m guessing they want to sell the flat in Madrid so they can pay easily for the new house and save a couple of years worth of rent. Now, she has a brother who is currently living in England. He wants to come back to Spain but not to his parents home, so… hey, free housing in Alicante! So yes, if Eric and I happen to move there, we’ll be living with my cousins.
The worst part is that their choice of city was determined only by being too lazy to find a proper job or having gone into too much debt or wanting to have a place for free and spend their salary on whatever. My choice was made because Alicante is the only University in Spain offering the doctorate program I’m interested in.
I’m not living with them. By any means. No way. So do I have to renounce to my Phd? Do I find another place, while they get that one for free? I’m just so so angry and upset.