Who are members of a statutory tenant’s family?

Wandsworth LBC v Randall CA The Telegraph 7 November

A four-bedroom house had been let to the defendant’s grandfather in 1975 on a periodic tenancy. By 31 December 2004, the defendant and his grandfather were living alone in the house and the tenancy had become a secure tenancy. On that date, the grandfather died and the defendant succeeded to the tenancy. The local authority informed him that he could not remain in the house, as the accommodation afforded by the house was more extensive than he reasonably required. The local authority served a notice stating that it would seek possession on the basis of the Housing Act 1985 Sch 2 Part III Ground 16. It issued proceedings relying on that ground. Between the service of the notice and the issue of proceedings, the defendant’s mother and half-sister had moved into the house.