You could try combined water or very diluted conditioner through it- that might help a bit with the frizz. But test some of the mohair first to make sure it doesn’t bleed-- that can be a problem with mohair that isn’t pocessed correctly. Take some hair, wet it, wrap it in a white paper towel and give it a squeeze. You shouldn’t see any color on the paper towel.
You can always pull out the bad hair and start again…but I know how painful/frustrating that is! Good luck Let me know if you have any questions.