Question: how to make fluffy jackets fluffy again?
Answer: First off - quit washing your hoodies. Unless your kid vomits spaghetti on you, spot clean that sucker.
When you do HAVE to wash it, quick gentle cycle it in cold water and don't use fabric softener.
Air dry your Sherpa or Fleece.
When it's done, use a bristle brush and gently comb it out in all directions.