> If this is a chronic thing, then perhaps there are some unsaid things that need to be said between the friends.

I have an idea for that! How about an app where you can write things to your friend, which are held in the system's escrow.

"unsaidthings.io"

Then a machine learning algorithm compares them for similarity/reciprocity. If they are similar, then the escrow is released, otherwise neither person knows whether the other submitted anything at all, or whether they did and it was different.

The prototype can skip the machine learning algorithm and instead let the people select from one of 64 possible messages that are compared according to a static table. Or else be allowed to compose sentences out of fragments guided by a "writing assistant" which guides their structure into possibilities that are easy to analyze.