maddy in a tier 2 area, households cannot visit another household inside. In your case, if one of the brothers were single, he could form a support bubble with your in laws and go in as much as he wants. But otherwise legally they cannot visit inside. They could meet outside ( public or private space with the rule of 6 ) and of course leave shopping. I think the difficulties faced in this type of situation are a real issue and also illustrate how difficult it would be to implement the protect the vulnerable / let everyone else live normally scenario. If it were me and I felt I had no alternative, bearing in mind the need to minimise risk, , I’d do a rota - one week on, two weeks off. Still illegal but would be less risky.