[Fey]

M'kay, good stuff for kitty tummies:
~Unflavoured/vanilla flavoured yogurt
~Canned and/or baby food in pumpkin
~Overcooked white rice
~Scrambled eggs

Start with the yogurt, it'll aid in rebuilding healthy cultures for digestion in their stomach. It's also mildly sweet so they should like it. Move onto the pumpkin, it's got lots of vitamins and proteins so if they're not eating enough it'll help.

Snuggle them often and feel their nose and ears. The ears should be mildly warm to the touch, not hot. The nose should be warm and dry, not wet. If push comes to shove talk to your vet about payments, but get them both in. Also, if you know one might be the 'carrier' maybe separate her/him from the rest until you have their symptoms under control.