Sorry to hear about your hubby's leg but he has done amazingly well, you sound like such a supportive wife so I'm sure he can shift the rest himself if you persevere together, 6 stone in 14 months is astounding!
I bet if he knuckled down with you he could be well on the way to a healthy weight in 2 years? In my (unasked for) opinion he's right to want to avoid surgery.
Congrats on the 'normal' BMI. You kick ass! You've also had three kids and weigh less than me....I deserve a slap on the wrist for that...