Help please!
Posting on behalf of a friend who is at their wits end.
They have had a rescue cat for several years who has always used a letterbox. Recently, he has started pooing outside as well but, even more recently, he has also taken to pooing in their hallway.
The other morning they found 4 poos in his favoured spot 
I wondered if it was because he was discovered to be toileting under the stairs but since that's been blocked off he's now chosen a spot close to it but my friend is getting so desperate about it he's beginning to wonder if they should rehome him!
He does have 2 other cats, they live together reasonably well and there aren't any signs of stressors that might be affecting this cat - though he does have quite a dominant personality.
He still uses the litter tray for both urination and defecation and its kept clean.
Feliway plugins are already used around the house.
Does anyone have any experience or advice about what might be causing this behaviour and how to stop it?
My friend is a soft old soul and would break his heart to rehome this cat but he's really struggling with this.