Summary
The horizontal range from which you can sleep in a bed is a 6x6 centered on the northwest corner of the head block of the bed, regardless of orientation. The result is that the range players can sleep in the bed will appear inconsistent when the bed is placed in different orientations, varying from 1 block to 3 blocks for each side.

Steps to reproduce:

1. Place down a bed in the 4 possible orientations (NSEW).
2. Attempt to sleep in the bed from different distances on each side.

Observed results
A sleeping range (the blocks where you can stand on and reach the bed to sleep in) as shown in mcbe_bed_range.png will be obtained. mcbe_bed_nwcorner.png shows that the range is centred on the north-west corner of the head block of the bed. White/gray blocks show the valid sleeping range, red shows the invalid sleeping range.

Expected results
java_bed_range.png shows the sleeping range on Java Edition (yellow shows the valid sleeping range with a half-block cutoff) - the range on Bedrock Edition does not have to follow this exactly, but should minimally be consistent on all sides (e.g. 2 blocks reach).