Bloat can happen in the middle of the night as well, as can gastric torsion. All it is is inflation of the stomach. GDV (torsion) is when it flips on itself. Make sure he has lots of water. Limiting water only pertains to during exercise. GDV is at highest risk after or during exercise. This can happen with water or food intake. It can happen on an empty stomach, but it is rare.