The knob just operates the mechanism. You need replacement parts for the operating mechanism, not the handle. If your husband is too lazy to fix it, it might be a good thing since it is easy to destroy a Delta faucet while taking it apart. Your safest thing since you are not familiar with it, is to call a plumber. If you try to repair it, and do it incorrectly or use too much force, you will wind up with a faucet in two pieces and very few plumbers know how to put them back together again and thus will have to install an entirely new faucet. This is big bucks.