As well as redundancy she is entitled to pay in lieu of notice. This is one week for each complete year of service, so if she has been there for 5 complete years she is still owed 4 weeks, as he gave her 1 week. Also, if she has not had her holiday entitlement this holiday year she might be entitled to some accrued holiday pay.
Suggest she contact ACAS helpline or goes to local CAB.
She will need to raise a grievance about it with the ex-employer & then go to an Employment Tribunal. CAB has booklets explaining this. There is a 3 month time limit for going to the Tribunal.