This is my concern as well. How could the neighbor even see him at 100 yards, at midnight?
Where is the information about her proposing to him? I missed that.
We still have no explanation for how he got back to the Emeryville marina after being deposited near the Costco (Solano Drive area) on the way between East Bay and Sacramento.
There are instagram maps showing the very long runs he took (certainly a 30 mile run is possible for him). Quite a high energy guy if after that very busy day, he not only goes for a bay cruise, but also a midnight bay swim.
If he did get out of the water, in those temperatures, and did not go to his own boat to change, that's indicative to me of a person in distress and/or some kind of agitated state where they aren't thinking clearly. He'd had a long day of dramatic events, IMO.