Did she sign anything before they changed their mind?
OK, sadly unless a contract is signed an offer can be withdrawn. However what your friend can do is:
1) Contact the Councillor - they are elected officials and can work to assist residents
2) Complain to the Chief Officer - they will investigate the complaint and report back. This office is independent of the Council and can fully examine everything that has gone on
3) Ombudsman - once you get a final written response from the Council then you can complain to the Local Government Ombudsman. They will examine the whole case. They offer a free service at: www.lgo.org.uk
Can I clarify anything about this today please?