Working with the elderly, I have known a fair few that either sleep on the sofa or in a recliner chair, some even without the recliner. they don't appear to come to any harm.
Mind you, just 2 days ago, one of my ladies in her own home, slept fully reclined, had a lightning storm that tripped the trip switch. She was now stuck in a reclined position in an electric recliner and couldnt get out of her chair to let me in. Fortunately I gained access by other methods!
I imagine people have died through such a problem, scary thought, maybe they should be fitted with emergency back up!!