According to Muslim law he was to be buried before sundown the following day and I doubt if any NAtion wanted his body.
That's exactly it .... no-one wanted him, the US did right by the Islamic world and buried him as prescribed by his faith, at sea, which is what Islam decrees is an acceptable alternative IF land burial is not possible within 24 hours of death.
From what I've read, prior to 'burying the body at sea' they offered his remains to Saudi Arabia to properly deal with and they refused. After that, you really have only one option. It's not like they were going to fly him back to the US and give him a proper funeral there or allow his remains to be sent somewhere else that might in some way become a sort of rallying point for similar thinking individuals.