If literal, it probably means that he will sling the other man over his shoulder and carry him (hold and take somewhere) like a sack of potatoes! Maybe the man being carried is wounded or sick, for example. If figurative, it probably means that he will do most of the work for the two of them in order to succeed at the task that faces them.
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A man says to another man: 'We're surviving this if I have to carry you the whole way.'