Preventing closure of UC claims when someone has LCWRA after 3 mths

I’m sure this has been discussed many times before, but I can’t find any relevant discussions so am asking again! I have a client who is undergoing radiotherapy but is not DS1500. Benefit check shows nil entitlement now due to husbands earnings, but £391pm after 3 mths when a LCWRA element will be applied. As UC claims are closed after a month if nil entitlement now, how do we get round this so that she can serve this 3 mth period then qualify?

See this recent thread.