I don't really understand this - does "kot" mean side of the family? Li se sè franck kot manma,mwen se frè franck kot papa sa vle di jonatha pa sè mwen.

Yes.

Frè kot papa meaning brother from the father's side ... a stepbrother
Li se sè m kot manman m meaning she's my sister from my mother's side meaning we have the same mom but not the same dad ... a step sister

Haitian Creole ↔ English Reference, Look up Haitian Creole and English Words