Unfortunatly Appys are notorious for craptacular tails lol. Keep it clean and brushed out. Good luck! Lol I have seen some appys with amazing tails and some with almost nothing.
I have a qh gelding that had his tail braided and then never taken out....for YEARS. When we got him we had to cut it all out. Its taken two years for it to grow back
Edit: if you have to cut on it, cut up and down through the hair, not across, that will help you keep some of the length. And, its kinda expensive, but you could order a small bottle of Wen. Its a conditioner that works wonders on my horses manes and tails. Cut very small amounts vertically in the tail and comb out as you go.
I have used regular conditioner, spray detanglers, and even hot oil treatments. The Wen works way better.