My friend told me the other day:
Robert ist einfach so sympathisch, den kann man nicht nicht mögen.
The entire sentence made sense
Robert is actually so nice, that you can't not like him.
However, when thinking about this sentence on the way home, I was wondering why my friend used "den" instead of "dass".
Robert ist einfach so sympathisch, dass man ihn nicht nicht mögen kann.
When he used the pronoun "den" I thought the sentence translated as
Robert is actually so nice, who you can't not like him.
Is that an accurate translation, or can "den" behave similarly to the english "that"? What purpose does "den" serve here from a grammatical perspective?
I would have thought "ihm" would have been the appropriate pronoun to use in this situation i.e. "him"