Sister is a social housing tenant, council have left a

Sister is a social housing tenant, council have left a vulnerable family with children newborn baby days old with heart defect. in a rat infested property and other disrepair issues been ongoing for 9 weeks they offered 3 days emergency accomodation to family was told to go back to property 5 rodents were found in.property and reported to them. Pest control had come out prior but were instructed by the council to treat for mice. Despite tenant (sister )saying its rat. After rats were found. All the senior managers are now trying to get all the repairs done as quickly as possible. Sister been bombarded with calls from pest control housing management and other subcontractors to carry out works. However its apparent that it's just quick temp fixes. Ie severe damp and mould issue contracter came in sprayed mold spray over it wiped it with a cloth and left. The council have acknowledged that due to works they carried out next door to my sis property workers made holes in walls and floor and created access points for rats to get in. Sister has sent over 20 emails pleading with council to find her alternative accommodation as she is out of hospital with the new baby. They said they have no emergency accomodation available and all the hostels they use are full. There is open rat bat all over the property. Pest control advised that property in that condition is in no way shape or form suitable for human inhabitance due to the amount of infestation in there. Letters emails voice recordings, doctors letters, pics. Have all been taken by my sister. Shes up to a stage 2 complaint. The urgency right now is for her and the children to be move out of there immediately. What are the next steps legally