Like I always say, there's no 'I' in "team". There is a 'me', though, if you jumble it up. — David Shore. Canadian television writer (born 1959)
Only two things you ignore: things that aren't important and things you wish weren't important, and wishing never works.
You're supposed to trust friends. You have no reason to be his friend? That is part of the pleasure of friendship: trusting without absolute evidence and then being rewarded for that trust.
It's a basic truth of the human condition that everybody lies. The only variable is about what. The weird thing about telling someone they're dying is it tends to focus their priorities. You find out what matters to them. What they're willing to die for. What they're willing to lie for.