Hi Joy,
I am so sorry for your loss and I hope I can help you plan a magical birthday for your son. The weather in June could not be better. The humidity is not at full strength so the thunderstorms will not be as frequent as later in the summer.
Since you will be a party of five, there are some rooms geared just for you. I have included a
link here for you to look at and get a feel of each resort. The All Star Music Resort Family Suite will have two bathrooms and a kitchenette for you to use. I think this is a better option than a room at Port Orleans Riverside where you will have a single bathroom.
The villas, while more expensive, do offer a full kitchen which can help on meals. You can cook here, and we usually eat breakfast in the room and then have a few dinners in the room as well. We even brought lunch into the park with us to feed the girls when they were little and got hungry.
I recommend looking at Mousesavers.com or Allearnet.com for deals at the Walt Disney World Resorts. Disney's site itself has good deals on trips which may include free dining if it is still being offered.
I wish you the most magical of vacations with your son!
Beth