do you know how to empty anal glands angela ? if not pop him along to a good groomer and they’ll show you and be cheaper than vets. that might help with scooting (bum along floor) scooting is usually as a result of being loose poops. might need a clean now but should clear once poop firms again 🙂 i dont expect he’ll be terribly happy about it with colitis too so if you dont trust him not to nip (i expect they might make you hold the head end!!) take a fabric muzzle for the little man 🙂
are there any signs of worms in him ? my advice would be worm naturally BUT this will scour the gut etc… which is already sore so maybe leave him a while for them to get nice and healthy. chemicals like milbemax wont help and if he is a sensitive dog he may well react to them at the moment too – he’s like us recovering, bleh !