My neighbor found a couple kittens abandoned at a work site. Their mama didn't show up at all by the time he left so he took them home. I told him to get kitten formula and not to feed them on their backs and to use a q-tip to stimulate them to poop. I gave him a can of soft food I had lying around to see if they would be interested. I think they're around 3 or 4 weeks old. Any other advice?