I haven't done enough research on bipolar; do I feel people use the term incorrectly -- similar to how people say I "love" this or I "love" you for that, YES! (I'm guilty of this)
People that haven't actually experienced or know someone who suffers from retardation, autism, depression, or bipolar may use terms without realizing the impact a true diagnosis has on an individual.
I truly believe cognitive therapy and taking responsibility for your emotions is similar to diet and exercise, and having a diagnosis (bipolar) is similar to hypothyroidism.
The individual needs to take responsibility for their life BUT if they're unable to see life rationally (1), then it doesn't matter how much exercise or dieting you do: the problem will remain.
This doesn't necessarily help you OP, ask him if he's seeing a doctor for it. If he is, respect that he is telling you the truth.
(1) Chemicals being produced in the correct amounts and maintaining the correct balance; reuptake drugs supposedly keep things circulating in the synapses.
Annoying Random Thought: People like Tom Cruise that think there is no need for medical intervention (medication), if a problem continues to hinder someone's life, are ignorant or extremely insensitive. Remember Oprah and the couch jumping!