He discovered his married sister having an affair with his best friend. Instead of being shamed or apologetic, she asked him for help finding someone who could impregnate her.
Another of Mervin's Mistaken Identities Tales
When a group of friends are out drinking while camping, a case of mistaken identity occurs in a dark tent at night to the surprise of the recipient.
A beer with my new landlord ends with me sucking him off. He had caught one of my Grindr hookups leaving my place and let it slip that he hadn't had a guy suck him off in over twenty years. That was my cue to get on my knees, release his cock from his speedo and show him what he has been missing out on.
Sharon flies to Tuscon to help her father-in-law who is drinking too much after the death of his wife. Sharon soon realized that 'dad' is horny and she is too and although against her better judgment an affair starts.
Damned if you do, damned if you don't! But eventually there comes a time when you have to say something. Short, mainly dialogue and written to confuse.