、。
Don't forget to go see Dad next week.
Literal
Next-week, forget-not-[negation-ずに] father [to-に] meet-give-me.
~ずに is a written/formal negative-adverbial form 'without doing X' — equivalent to ~ないで but more literary. 忘れずに = 'without forgetting / don't forget to.' Built as the negative masu-stem (忘れ) + ずに. Common in written instructions and formal speech.