Welcome to the forum Aamna - and thank you so much for getting the budgies away from the lady!
Some budgies don't like to bathe in water as much as they like to rub their bodies against the wet leaves so, do as Wolf says and put a large and really wet (dripping!) leaf of something like romaine lettuce on the bottom of the cage and I bet you they will eventually 'bathe' in it. And it's the CUTEST thing, too!

because they squat down and fluffing all their feathers until they look like little balls, they rub themselves on the wet leaves while they flutter their wings -you'll see!
Also, if they had been fed a bad diet, I suggest you get some good quality bird multivitamin/mineral supplement and add it to some kind of soft food -if you don't want to go with gloop, you can always cook couscous, pastina or some whole grain and mix the powder vitamins with it.