Now you are depending on an absurdly literal reading of the tale to exaggerate its implausibility.
It is a well-established fact that North Korea suffered several years of famine in the mid 90s, with at least 1/4 million fatalities and probably much higher, arising from a combination of the loss of economic support from the former USSR, El Niño and a kleptocratic bureaucracy. In such circumstances, it would not be that implausible if some peasants reverted to the winter survival techniques used by millenia of nomads and subsistence farmers.
As for lying in the sun: if you are cold, famished, and have exhausted all the new-grown food that the spring has produced so far, then perhaps it is the best you can do.