Inspired by Monkey's friend in Texas who emailed a vexing dilemma that I think most can relate to in general terms!
We have all probably made dumb excuses to get out of something at one point or another, but I think as people get older and narrow down their friend base they tend to get more honest instead of making up excuses.
That said, once in awhile when a very big life altering event happens, a close friend that you assume/ think would step up to at least acknowledge said big life event - via phone, text, email or snail mail - just completely bails out and goes dark. Missing in Action. Not to be heard from for months until one random day, boom. They reach out like no time has passed, like no change has occurred, like you should just pick up where you left off.
Then, you ask said friend, "where have you been?" and the lame excuse lands on your shoulders like an unanticipated bird crap falling out of the sky.
Do you: a) call them out on the lame excuse and ask what really happened b) ignore it and move forward c) other?!
Personally I think you have to weigh the importance of the friend and the depth of the damage done by them going dark.
If they are important to you and the damage isn't permanent, call them on it. You might not get a real answer because the truth is probably now magnified into an embarrassing boulder that was once a pebble because so much time has passed. BUT in some ways it puts them on notice that you won't continue to be treated that way.