As long as it's kept in the SEALED antistatic bag and he/she takes a little care it'll be fine.
But why take it out of packaging designed to protect it?
I'm sure there will be no problems but be aware that exporting goods can be a minefield:
Be aware that Customs officers are paid to be suspicious, they may think your cousin is trying to smuggle the goods into your country without paying the relevant duties and taxes.
Also check it is legal to export to your country, like all countries, the USA restricts the export of high tech goods and while it may be legal it may require a license or additional paperwork.
Very heavy point:
The Feds tale a very, very dim view of smuggling and they have NO sense of humour AT ALL.