He needs to go and make an appointment with his counselor and let them know what the facts are in the most respectful way. If there is something wrond, they will fix it.

Not directly. Indirectly you can through third-party care package vendors or send money to their commissary account and they can buy goodies at the commissary

Yes

Commissary is once a week in most places. We post the commissary lists for the facility on their InmateAid page, especially federal prison.

Inmates go through an orientation period. Usually inmates can shop within a week of arrival and if they have money on their books

Not normally. If you are in federal, you cannot. If you are going to state, it depends on which but most do not permit pre-ordering. You can always set up your money beforehand if you have an ID number and shop the day you are eligible.

The prison commissary sells envelopes, pens, paper and stamps. They are reasonably priced. If the inmate is indigent, there are provisions made to gift these items to them.

Sneakers are a real commodity in prison. Commissary sells sneakers and other shoe "upgrades" like boots, etc. The charges range from $50-125. There is also a "secondary market" where inmates sell used shoes either from inmates that have upgraded theirs or when someone is released as they departing inmates oftentimes symbolically leave their shoes behind.

not long

Inmates shop at the commissary normally once per week. You can place money on their boks using the various inmate money transfer companies. There is either a weekly or monthly maximum spend limit ($75/wk - $340/mo). You cannot normally shop for them unless the facility has an arrangement with a vendor that sells commissary baskets. You would have to check with the exact facility to see if they have a company for you to contact.