How to care for a wild dove?

Buy a large parrot cage, since the bird was wild and will not do well in a small cage. You could also buy an indoor or outdoor aviary. Buy dove food and put in multiple bowls. Use natural branches that are not toxic to birds and connect them all together so the bird can move around from perch to perch if it can't fly. A wild bird doesn't need toys. No matter what, you have to take it to a vet and get it checked out. If the vet says it should go to a rehab person, your sister needs to realize that what she wants isn't best for the bird and if she wants it to live, it should go to the rehab. Best of luck.