It's pretty much the norm for persons following ANY diet plan, whether it's lowFAT, lowCALORIE or lowCARB -- stopping the diet, and reverting back to previous eating patterns and food choices will pack the pounds back on, and then some.
All of the popular low-carb programs include a Maintenance component. Atkins presents the directions very specifically in Chapters 19, 20 and 23. Protein Power in Chapter 5 ... etc.
Although you're responsible for the menu choices and food preparation in your home, ultimately the choice for health is your husband's. If he hasn't actually read the complete Atkins program book (or other low-carb book -- can be borrowed from the library) ... he's actually doing himself a disservice. I'm not sure from reading your posts what his health concerns are, other than weight problem ... the thing he needs to accept is that these problems aren't going to disappear when he's lost the lbs. What he will have achieved through low-carbing is CONTROL over his weight problem, and CONTROL over any related health problems .. heart, cholesterol etc. But they will still always be there, ready to resurface and become a serious problem again if he decides to not keep things under control any more.
Will he never be able to eat potatoes or bread again. Possibly, but the chances are that he will be able to have these things again in future, in a CONTROLLED manner. Starches and sugars are what led to the overweight and health problems, and they will do so again if allowed.
As for increasing carbs now, from another post you've written ... if he is losing lbs in a slow but stead manner, then it should be reasonable to add back a few carbs, gradually ... give the body a chance to adapt to the higher carb level before adding more. Again, Atkins explains this in detail in his book. He call this OWL Ongoing Weight Loss, and carbs are added back in 5-gram increments .. in the form of larger portions of vegetables and salads mostly.
hope this has been helpful
Doreen