That looks authentic. And it looks to me that someone soaked it in Oxyclean or something of the sort. They should have tippy-toed up to it gradually, a little at a time, instead of declaring chemical warfare on it. I'm ok with a water soak, but not too keen on bleaches and such.
I can see where the card was bleached, card was gluded into a album, it would appear someone told him how to remove stains-- won't work- card is real- but value ??. I have received cards over the years from people that I find are bleached and they can't remove the stain- I just return the card to them and tell them someone already made a mess of the card.