I don't have much advice because I haven't been in this situation.. Only thing I can offer is maybe give him dinner earlier? He could possibly be too tired by 6. Sometimes we eat dinner at 4:30 but most nights it is 5:30ish (at the latest) although the last 2 nights have been 6 and the kids were feral but I am going off topic now

Can he help you prepare any part of the meal? Maybe when you go to the shops get him to put the veggies in the bag, pick out the meat (with your guidance) Then when you get home he can put the veges in the saucepan ect...