If this "stack" is coming at me then C-H is just completely and utterly clueless
Lets look at the many things wrong with this picture.
1. The army has no road network by the looks of things so will take 3-4 turns minimum to be outside either of my cities
2. There is ONE catapult... so he's either going to bombard forever (which surely is too stupid for anyone) or take shots at my units behind cultural defenses
3) I have been able to see this stack move because of my galley so there is no possibility of surprise. Plus I have a chariot in his lands that can easily check for reinforcements.
4) I will have longbows, maces and catapults to defend plus some outdated trash for collateral bait.
5) He can't fork my cities and I will have engineering so can use the majority of my forces to defend at whatever city he chooses to go for.
6) I have an abundance of pop to whip if need be - plus Qarth has decent production that is still boosted by a Golden Age so if needed I can have walls plus more longbows pretty quickly
7) He is so far behind in tech - including military tech that its insane given he got a super-potential city from B4ndit early on with next to no initial costs.
8) I have not done a thing wrong to him this game, even given him an excess luxury to help with happiness during his war with eastway
So if he's doing this to me, he can't have a single good reason.
Why not attack B4ndit who he warred with in the early game and is now being attacked by eastway?
Or why not build up a stack that is actually credible and try and attack eastway when peace runs out if he wants to indulge in some pseudo-erotic suicidal wank-fantasy of attacking someone for little to no benefit?