Put hoof heal on it!! I love this so much and it’s really helped my horses cracks. Also take a look at a supplement called “Dac Foundation” it has done wonders at growing hoof out
Keep him out of the mud as best as you can! The horse I ride, king just recovered from thrush on his feet and he now has shoes, we suspect it was because of the rain!
Use magic cushion ! I love that stuff so much when ever my pony has a crack I pack his feet with it and leave it on for 2-3 days and then it's perfect again 😊