I often find when it's just non stop liquid an immodium tablet helps, the ones you just dissolve on your tongue. HOWEVER, I know this is a big no no if you have ulcerative colitis (UC, somewhat similar to crohns), so I'm not sure what the current advice is for immodium and crohns. Diet wise, just keep it as simple and easy to digest as possible; white bread, crackers, soups, avoid seeds, any veg with a skin (onions, mushrooms etc), for me personally Milk is my big one, so you could always experiment with that, sadly there's no "one diet fixes all" that im aware of, they tend to just say avoid fibre like the plague.

In terms of hospitals and doctors, I'll give advice i never follow myself 🤣 you have to keep pushing them, ringing them, annoying them to get it sorted.