The honest answer first: no breed is hypoallergenic
For most allergy sufferers, this breed is not a good choice, and the reason sits in biology rather than grooming effort. Cat allergy is mainly a reaction to proteins in skin flakes, saliva and skin oils, and every cat produces them, including this breed. Individual Norwegian Forest Cats vary, and you will meet people who react less to one particular cat, but variation between individuals is not the same as a reliably low-allergy breed. Anyone promising you a hypoallergenic Wegie is selling you a hope, not a fact, and an allergy sufferer who buys on that promise is the person most likely to face a heartbreaking return a month later.
Why this particular coat makes the bet worse
Some short-coated breeds at least limit how much allergen travels around the house. The Norwegian Forest Cat goes the other way. This large Scandinavian breed carries a dense water-shedding double coat, with a woolly undercoat that blows out heavily as seasons change, plus a full ruff and tufted ears and paws. Hair itself is not the allergen, but shed hair and dander ride together across carpets, bedding and clothing, and a coat this generous distributes them generously too. Regular brushing contains the spread somewhat, yet the person who most needs the brushing done is often the person who reacts worst to doing it.
Test with the exact cat, not the breed label
If your heart is set on this breed, replace the label with evidence. Arrange several visits with the specific kitten or adult you hope to bring home, handle the cat, sit in the room where it lives, and press your face near the coat the way you would at home, then watch your symptoms over the following day rather than the following hour. Ask whether an adult cat with a trial or return agreement is possible, since kittens produce less allergen than mature cats and a kitten who seems fine can become a problem as an adult coat and adult glands arrive. Talk to your own doctor about your results before deciding, especially where asthma is part of the picture.
If you proceed, build the house around the allergy
A determined household can lower exposure without pretending it can be eliminated. Keep the allergic person's bedroom a cat-free zone with the door shut, wash hands after handling, brush the cat in one easy-clean spot, vacuum soft furnishings often, and keep bedding washed on a steady rhythm. Decide honestly who does the litter tray and grooming if symptoms flare, because a plan that depends on the allergic person doing everything will collapse. Keep notes on what actually eases your own reactions during the trial visits instead of relying on generic lists. When you are weighing this cat against those trial notes, put a follow-up question to KinsLe's Kimmy; she answers using the KinsLe Answers library.