The ultra lite weight of hospital medical bed models, and the hand crank for raising the torso and feet up/down vs square battery backup?

I just bought a typical used bed but don’t understand why the “light weight” status is given to this bed that to me feels like a TON. There's luckily only 8 stair steps to my dad's bedroom but still so dangerous even getting it out of the SUV for my strong son and relative to maneuver.
My 95 year old dad doesn’t need it yet but it would be nice to have him get to bed if he’s tired and sit up to watch TV in case he just ate an hour ago and can’t lay down to sleep for another 2 hours so he can digest the food in his stomach first.
Problem is I think I bought a bed for a heavy person and my dad is only 113 lbs. But they all look the same even the hospice kind my mom had.
The other thing is I can’t find a model with the manual crank for raising the torso and feet up and down during a power failure or if the little square battery back dies. I like the security of NOT relying on a battery for such things. This house flooded 2-1/2 feet so luckily my dad's room is now up in split level bedroom. But what happens when I have to put the bed downstairs and the house might flood again or there’s a power failure?
I loved my mom's bed which had a manual 20 in long crank tool that raises the torso and feet up/down in addition to also having the centered manual crank to raise and lower the whole bed along with electrical power. Anyone in healthcare know much about hospital and medical bed models? And their weight?
This model says 450 lbs and that the bed itself weights 175 lbs. Is there a frame that might actually be 100 lbs perhaps? Is there such a thing? I see the same model at 155 lbs. I even called the manufacturer but no one answered and gave me an email which I sent my question but no response yet.
What do people do if there’s a power failure and battery only works for 9 uses of raising and lowering? There is no insert for any crank tool on models that the medical bed supply company sells which works to raise and lower all motors. Very strange.
Perhaps the fastener nut that holds the torso part of the metal frame has to be manually removed and then the patients torso can be lowered and raised?