Feels dizzy back of head. Example; sharp turn as passenger in car can cause feeling and can last hours. Worse lying down. Has minor Hemolytic anemia?

BPPV? S/He might have benign paroxysmal postural vertigo. BPPV is very common, occuring in up to 5% of the population. Mostly in older persons but can occur at any age. Just like certain positions or movements can trigger it, positional procedures usually can reverse it quickly. Unrelated to anemia, hemolytic or other. Google BPPV for lots of websites; the Wikipedia article is pretty good.