The Disney Vero Resort is located in a high-end residential area so there are no other resorts "right there". As you may have seen mentioned, it's really Wabasso/Orchid Island and not Vero Beach proper.
A drive down A1A (I don't think it's no more than 15 minutes) will take you to the area along the water where more resorts are located. I don't know how it fared in the hurricane and if/when it will open but the Holiday Inn in Vero is very nice and is located right on the ocean.
If they really want to find less expensive options, they should move inland. It will be a longer drive to see you but out by the outlet center on SR-60 there are some hotels as well.
People who are visiting the resort for dinner, etc. are instructed to park in the lot across the street. They then use the tunnel to walk under A1A. The hotel is a public space so they could certainly come into the resort. I think they've now put a gate to the beach access so you'd have to help them out on that one. The beach itself all along Florida is open to everyone. There is also a public beach with lifeguards right next door. They took a real beating in the hurricane but I'm sure it'll be up again before long.