[Ellie May]

Water should be left out all day. Night time - some dogs won't get up to drink. Can't hurt to leave it out though.

I'd feed 4-6 times a day because you know he is prone to hypo.
Free feeding kibble is completely fine, but with his history you need to make sure he is eating several times a day. It would be easier for me to keep tabs by meal feeding.

Depending on what the vet thinks about possible recurrence they may prefer that you get up every 2-4 hours and feed.

Nutrical is good stuff, but as said above it needs to be followed by quality food or it can lead to a crash. It is great for when the dog is actively hypo but regular meals are best otherwise.