Does your husband want to loose weight, or is he just saying so to satisfy his doctor and you?
He won¨t loose weight unless he is prepared to make an effort.
To help him, throw out all the snacks, whether crisps, bicuits, chocolate etc, plus all soft drinks (including the so-called diet coke and sugarfree this and that ).
Keep treacle, sugar, brown sugar, marmelade, jam and honey locked away.
Serve smaller portions of food - use smaller plates. That way the difference in portion size isn't so noticable.
If you can, get him to agree that it is three meals a day and nothing in between.
Discuss with him which form of exercise he finds least boring
Walking, cycling on a conventional bike, not one with and electric motor, jogging etc. and do it with him EVERY DAY, or at least six days a week.
If he does not want to loose weight, you cannot make him - the decision has to be his and his alone, but you can point out that you have no desire to be rid of him to whichever illness his doctor has pointed out may well be the result of h is life style.
But there again - if your husband would rather live life his way rather than live a long life, he will do as he will do to quote the Rum Tum Tugger and there is nothing at all you can do about that!