When Is Free, Unfree?

Jean- Paul Sartre was a existentialism who believed in negation, that people can always choose. He uses the dialectic to explain, but not in the same as Hegel, Sartre uses the Master/ Slave dialectic. As we discussed Sartre in class this week, we came across that there is never a case where a person is absolutely unfree. A freedom is someone who has the ability to choose on their own and do what they want on their own. Therefore, if a person happens to be alive and breathing, then they are a freedom. What about if this person is barely alive? This person needs a machine to breath for them, and they are severely brain dead. This person is still alive and functioning, but only through the help of a machine. Would this person be considered a freedom. I feel that they are not a freedom because they cannot choose or do things on their own. They are not even telling themselves to breathe! This person does not have a free mind or body, so how could they be seen as a free? According to Sartre though, there is never a case where a person in considered unfree.  So now can anyone answer my question from this example? Is there really never a case where a person is considered unfree?