Intermittent draining of a chest tube

I am a hospice nurse not too familiar with this situation.

I have a patient with lung cancer who has a chest tube which is to be drained 3 times per week.
Each time we drain it we get approximately 500 ccs of fluid. Her other lung has been pasted.

The doctor has ordered the tube drained 3 times a week but the case manager and DON, both former
ICU nurses with lots of critical care experience, say draining it more than 2 times a week will increase the
chance of collapsing the lung. I am not following their logic in this and am trying to research the answer
rather than going for the easy answer and just asking.

Can any of you share your thoughts about this?

Many thanks