We have 3 dogs, 2 Cockers and a toy Poodle. They all have short haircuts. I have a heavy duty front load Maytag washer and Maytag dryer. I wash them in hot water and have had no problem with hair in the washer. As for the dryer, I dry on hot. My filter is pretty loaded at the end of the cycle but I do not have any problems with leftover hair after I clean that out.
Maybe a damp towel in the dryer afterwards would help. Also, I keep "dog towels" on hand and they get washed separately so maybe you could wash those after the blankets to get any leftover out for you.
Best wishes to you and your little one. Enjoy it, they grow up TOO fast and yes, they will still surprise you even at 12!!