The article doesn’t say who he did not work for. Nor does it say who all he worked for. It just says he was on Condoleeza’s security detail. That does not cover the entirety of his abbreviated career. Clearly he had to work for someone after Rice.
So far the only mention of him on non-conspiracy site is that whatever happened to him a distant relative expressing condolences called it a “tragic accident.” No mention of what happened.
His last known clothing while alive was khaki pants and a blue oxford shirt.. no description of footwear … he was sighted at 10 pm or so, he had been driving a gray SUV. It doesn’t sound like he was going boating.... but if that was when he died then poor lighting may have contributed to whatever happened.
There are all kinds of conspiracy sites posting theories but all seem to be doing it with no more information than is on this thread.