Is it possible for a grown man to.....?

Fall off a waterbed and get stuck between the bed & the wall, get stuck & die of asphyxiation? This happened to my dad. He layed down on one side & rolled all the way over to the other side, rolled off the bed & got wedged between the wall and bed frame. Not the mattress & bed frame. My stepmom says she couldn't get him out & he died from suffocation from the pressure of the weight on his chest. He was intoxicated I might add but wouldn't it make more sense that he would sink between the matress & bed frame & how did he make it all the way across the bed without this happening..... Its a tragedy & I still can't make sense of it. Do you think this is likely or should I suspect foul play? He was a strong man too, not fat but not small. Just average but strong.... What's your input on this situation? And do you think she really couldn't get him out? I am not making aCcusations, just trying to make sense of it. I know this is posted in the wrong category but I am not sure where it belongs. Sorry & Thanks.