Ugh gastro is horrible! I would suggest no solids for him for at least 24 hours.

DS no 3 had lots of feeding issues, BF until 11.5 months (far less than the first 2), and always had to have comp bottle feeds. I was a bit worried about how to stop bottles but he got a bad gastro attack, just like Nixon, a week after his first birthday. He threw up anything with milk in it: formula, cow's milk, goat's milk. I ended up giving him flat Sprite and that electolyte replacement drink you can get at the chemist, for about 3 days. (can't remember the name of it?? but that is what it's meant for. Tiggy should know.)
And lol, once that was over so were the bottles! I'm not saying this will or should happen to Nixon, just that I know what it's like to wipe up after a big spew! They always seem so cheerful after one too. His poor little tummy must feel so irritated.

I hope you don't get it too! (or dh, I hate it when men are sick).