Sodium is a problem for some people, but it's also not a problem for some people. It's certainly something to pay attention to, but probably not as important as the many other important things to pay attention to, unless his blood pressure is affected by sodium and it's already too high.

>and nearly all of his self reported vitamin/mineral intake was about 1/3 of the daily recommended levels.

Yeah, and that is above average. You are seriously over-estimating how healthy the average american's diet is. This is one of the big reasons people are interested in soylent, getting 100% of all your vitamins and minerals by just eating "real food" is actually very difficult.