I'm confused by your question. If it is can you stay some night on points and some on cash the answer is yes. Make sure you book cash ressie through DVC though, it is the only way to link the ressies so you don't have to check in and out. Also there could be a DVC discount.
If the question was i.e. the room is 22 points per night and I only have 8 points left, the answer is no. Each night is either all cash or all points.