Ah well I just cook gluten free spaghetti for everyone, I can't tell the difference anymore.
Similarly gluten free lasagne sheets are indistinguishable from normal ones so everyone gets gluten free lasagne (I use the jarred dolmio cheese sauce to make it as its gluten free as standard)
Schar do good frozen margarita pizzas, they are currently on offer in Asda for 2 for £3.50 - we just add our own toppings.
I find eating out not too bad - trip advisor lets you search for 'gluten free' so you can find places in the area that other people have recommended for gluten free.
Lots of fish and chip shops do gluten free these days - it's worth having a google to see, and even the ones that don't tend to keep the chips separate so he might still be able to have chips.
McDonalds will do you a burger etc without the bun if he took his own bun.
Typical meals in our house are:
Spag Bol
Sausage and Mash (I use Asda own brand GF gravy)
Cottage Pie
Burger and Chips - the coeliacs have a M&S bun
Gammon and Chips
Home made potato wedges and chicken pieces (I get thighs and drumsticks and sprinkle with salt or sweet chilli sauce)
Stir fries with rice noodles or rice
Curries with rice
M&S gluten free chicken goujons (delicious!)
Pizza
Stuffed baked potatoes
Roasts - it's really easy to make GF Yorkshire puddings