Horses Founder

We have a gelding Tenesee Walker 8-12 Years old. Foundered 4 days ago. It is supposed to similar to Sugar diabetes. Vet gave it meds and said may or may not survive. His joints are crippling and he is bloated, neck swollen. What can be done to have him healthy, happy, walking and running again? He has been cut back severly on food to almost nothing and is drinking water, pooping a little still. Tweet