Terrible housing situation.. help?

So we moved into our new house (all third year students) at the start of October, it was in a terrible state because the previous tenants had moved out the DAY before and the landlord was profusely apologizing to us, saying she'd get all the repairs done. 2 weeks later and there is little progress and we have so many issues. Water is leaking from the kitchen roof into the light, you can't switch it on or you risk being electrocuted. The electrician came and we find out the landlord lied to him and just told him that the light was broken so he had no idea it was actually water leaking into the light. Water leaks into the oven and now water is leaking from my room every time someone uses the shower. The landlord says she will fix the roof herself but it's already been two weeks, she is not a professional and refuses to hire professional help. She comes around once a week and towards the end of the day (shes always late) to complete minor tasks such as hoovering or painting when we have much bigger issues at hand.

Today the electrician came and discovered that underneath the plastic floor the floor is black and rotting and the wooden floor bean holding the bathroom up is black. There is also cracks in the shower which is why water is seeping down my walls (I'm downstairs). She is always nervous when she comes round and promises to knock off a week's rent but says she can't make the place "something it's not". The people (a couple) I'm living with are furious and have already got into a fight with the landlord's husband, we've made a list of everything wrong with the house and the couple are getting in contact with the council and student union and trying to get the landlord's license revoked. (oven door broken, pipes smell, we have a mini fridge for a fridge, everything made of cork including the stairs, it feels like everything hasnt been touched since 1970, mattresses filthy, dirt everywhere, so much more)

Today they packed a bag just in case we are told to leave by the council. I told my mum about the situation and though she agrees the landlord is incompetent and refuses to spend any money, she thinks the couple are being dramatic and will just get evicted and that they need to just accept it. The couple says they won't pay the next rent unless everything is fixed but they hope they dont have to move. I'm friends with them but I have no idea what to do and what's going to happen. Thoughts? Advice?