11yr old Unilateral Hip Spica?

You might have asked this at the time that he was having the cast put on...

Call the doctor back tomorrow and ask about it. If he's in a spica cast, it's probably going to be a while. Make sure you are very well informed on how to take care of him, including the cast and his skin around and under the cast.

Generally about four to six weeks, probably six.

Different states have different regulations, but you may be able to get a home school teacher for him. Or, at least his teachers can give you work to cover while he is bedridden. I know you may not want to think of this right now, but it is important that he not fall too far behind in his work. I hope you were given instructions on cast care, skin care, hygiene and the like. Some insurance plans allow for a visiting nurse once or twice a week. Make use of this if you can.

When the cast is removed, plan on some rehab. Children generally rehab much faster than adults, but still he will not go straight from the bed to normal walking. His right leg might look visibly thinner. This is temporary.

Hopefully you can get some library books to occupy him some of the time. Puzzles and games, too. Don't rely just on television.