I think we've been lucky! No more sign of colic, and Fonti's leg is back to normal. Yesterday I spent the day in the stable and brought my books with me so that I could study and at the same time keep an eye on him.
Today I jogged him 30-40 min in the indoor arena, and he seemed fit and ready to work. Since we weren't going to work very hard today, I spent some time concentrating on the basics. We spent most of the time trotting in a long, low form, trying to keep 3-4 m away from the wall, which for me is the easiest way to check that my outside aids are working properly and that on both hands Fonti listens to my left leg (on the left hand, he tends to fall to the inside and vice versa). I also focused on keeping my hands soft, and not lock them as I sometimes do when we don't agree on things. Fonti is a good teacher - when my hands are soft, he keeps his end of the connection soft, and when my hands harden he leans on the bit and pulls back.
All in all we had a good day today, and I'm just so happy that he's healthy and happy again.