Young cats still 'nursing'?

Hi everyone,
My sister has two sibling cats(1 boy & 1 girl), about 9 months old, who still suck on clothes or blankets while they are making pudding/kneading bread!
My sister is sure that the people she got the kittens from lied about their ages so they could get rid of them sooner- so they we not properly weened!
Both cats will cuddle up to a blanket(near a human) and knead it while sucking on it endlessly!
Any hints on what to do to cease this behaviour?

Are they actually eating it or just sucking on it? If they're not doing any harm I'd be inclined to let them keep doing it

I imagine they grow out of it as they get bigger... Hopefully someone else will help you with your question

My sister has 2 tuxedos that were taken from their mother at 5 weeks, they are now 4 yrs old and still suckle of clothing/blanket. We've never done anything to discourage it as we know they are doing it for comfort.

Kittens that are taken away from mom under 10 weeks old will almost always have the "sucking" problems. Some outgrow it but many do not. As long as the cats are not eating the fabric I wouldn't worry too much. If they are chewing on the fabric too, then spray it with a little of Bitter Apple spray to discourage them.

Its a comfort thing mainly, but can be a sign of being weaned too soon or taken from mom too soon. How old were they when you got them (and how old were they really?)

My sister said the people she got them from told her they were 6 weeks old! I would be inclined to say they may have been younger, they were so tiny!
Anyhow, the bro and sis just kinda lick the blankets while kneading them, not really chewing them...
It's not really a big deal, but sometimes they will do it for almost half an hour!