When you sneak on the bed while the villager is on it, it pushes him. You could also glitch him into blocks and he wont sufficate.

Put the summary of the bug you're having here

*What I expected to happen was...:*For the villager to die or to be booted out of the bed

What actually happened was...:

Villager stayed in bed, but was pushed to the edge and glitched into a block

Steps to Reproduce:

1. Lock villager in house
2. Sneak on bed
3. Push villager head