I am sorry but if you have done a lot of research before you got him why do you need to ask what they can be fed?
You can not keep him in a closet either,he needs to have light and heat at that age.
An indoor rabbit or guineapig cage can be used with a heat bulb above one side for heat.

If you are planning on having him indoors the only thing i can say is do not do it, They are very messy and will soon stink the place out