You can now buy sausages made of chicken or lamb, which will be much lower in fat content that pork or beef ones. You should be able to find them in any supermarket, but failing that the nearest Hallal butcher will propably make his own.
Grilled with no or very little cooking oil instead of fried will also lower the fat content of the meal.
Not to be eaten every day, but once in a while they probably will do no harm.
Frozen chips can be done in the oven rather than deep fried.
No one who has had a painful attack of gall stones will willingly risk another one, so your husband if he realises that a new attack will be the consequence of not adopting the new diet may well be more amenable to more vegetables and less meat - the price of fish these days rather rules it out as an alternative, and of course you ought to avoid fatter fish like herrings and salmon.