My opinion, based on what I would do - I wouldn't assist just yet. First thing I'd do, is take them to be checked out, to make doubly sure that RI didn't sneak back in. Once that's absolutely out of the picture, I'd do a vitamin B shot to stimulate appetite. My vet suggested it a couple years ago for an RI animal that had come to me from a less than reputable person sick and thin already. I fought the RI for months before we finally kicked it, even having to gavage feed her a few times just to keep her alive. I hope I never have to do that again. Anyhow, we kicked the RI, and she just wouldn't eat. You could see her ribs and everything under all her baggy skin. Vet recommended the B shot, and gave me info to do it. (she's cool like that, we've built a nice relationship over time) I gave the snake the shot, and within a week she was back to eating finally.

I gave the B shot to one other animal who was recovering and similarly thin, and got the same results. I wouldn't use this stuff on an animal that's just regularly gone off feed like they just do sometimes, but I would definitely use this again before moving to assist feeding.

It's something for you and your vet to look into. They may even have the stuff lying around to give the injection for you right there at the office.

Are they drinking? They might need some fluids as well. Soak if you need to.