Kate has given a good answer for everyday English. In ordinary conversation, we usually would say "Thanks for being so kind and patient with me." If we wanted to be really proper, then we could use both prepositions: "Thanks for being so kind to and patient with me." Honestly, that strikes me as much too formal for this sentence, but if it were an essay for school, then it would be appropriate.

Yes, “with” is a better choice. If it was just “kind” then you could say “kind to me,” but “patient” needs “with.” “Kind with me” on its own isn’t wrong, but it’s less natural than “kind to” for a person.

(I ask this coz I'm not very sure about the preposition. Maybe I should use 'with' etc?)