firstly she can get some proper kitten milk formula from her vet .. cimicat or equivelent, so maybe the mum cat wont feel so stressed if the kitten drinks some of that.
Ive heard about quite a few kittens that age not wanting to wean but a couple of weeks can make alot of difference, she could try a tiny bit of raw mince, again heard lots of kittens starting off on that.
hills a/d from the vet is another good one to try, its like a pate type food and can be warmed up. Or my cat likes hi life petit pate tins.
also some kittens actually seem to take to dry food over wet food so she could give that a go, royal canin kitten is good as its tiny little kibbles or most love the hills but there are a few other high quality brands aswell.
She could feed mum along side the kittens as they will copy her but i wouldnt be panicking just yet, not for a couple of weeks.
