I could write you pages on Cushing's syndrome, but what if it turns out
your brother doesn't have it? His symptoms really don't sound
particularly characteristic of Cushing's - has his physical appearance
changed at all over the past few weeks/months? On the whole I think you
should wait until the tests have been completed before getting too
involved in the subject - believe me, it's very complex. Incidentally,
Cushing's syndrome has several causes, one of which is a pituitary
tumour, but the tumour in this case is very small and doesn't lead to
pressure effects.

Jeremy Fletcher (UK endocrinologist)