Generally it's 5 years, although there are a couple of conditions in this link which state it could be less, but neither of which apply to the OP.
yea..its 5 years,you right here.
Without her having that, he stands no chance as a non EEA member, of legally being able to stay in the UK
i think its incorrect..he has right to reside as a family member of EU state,but he has not right of permanent residence in the UK
he can purse any economic activity,like work or study but has limited access to welfare system without permanent residency.
there are 2 types of "rights to reside" one is for benefit purpose and one ordinary. its all BS created by UK to avoid having problems with EU commission and refuse poles any access to benefits.its abit complicated,but that was the idea.
gov.uk/right-to-reside
have been refused on the grounds that he has no entitlement to residency because maybe his wife has none either.
no...his wife has right to reside so does he.he doesnt need to be worry about his being legally in the UK as a family member,he can work,study ect...what he doesn't have right to is "permament residency" status,which gives full benefits access.