The fur collar of clothes will be very hard after being washed. The methods to soften it are:

Soak it in fabric softener for a few minutes and then dry it. Try to avoid direct sunlight when drying.

If the fur collar is detachable, you can remove the fur collar when washing clothes, which can reduce the number of times the fur collar is washed, because the fur collar will become hard if washed too often.

After washing the fur collar of your clothes, it is best not to expose it to the sun, otherwise the fur collar will become hard.