friend just got diagnosed with Crohn’s disease.. how do i help? ?

It’s good that you have been doing research to understand more about her condition, but just be aware that you don’t bombard her with information. You might know things that can help her with this condition, but this could also be overwhelming for her to get lots of advice. Check with her to see if she wants any advice or tips. She may welcome the advice because she just got diagnosed and doesn't know much about it, but she may not want all the advice, so just ask her and be a supportive friend. Be sensitive about the fact that she may go to the bathroom more often, be patient and don’t draw any attention to the stops as this could embarrass her.

She may also cancel plans unexpectedly because of the illness (she may have symptoms/flare ups), so just be patient, understanding and don’t push her to go out if all she wants to do is stay in. Don’t take it personally because this can happen. Respect her decisions and don’t play investigator saying that it’s because of this or that, that caused the flare up. If they blame themselves for it then just reassure them that it’s no one’s fault that these things can happen. Be respectful of the choices she makes regarding the condition and if you're eating in, or if you are eating out, be mindful of their dietary needs. This might just be asking her what she wants to eat or cooking something that limits the use of triggers for them. Just be a supportive friend really.

It's too bad  your friend is ill, but she needs to get through this on her own. You can't fix her, and she is the person responsible to make sure she follows her diet and doctor's orders.  You can't do that for her, either.

and i don't understand why you think you'd do or say something "wrong".  If you're that close as friends, you ought to be able to ask her about it and how she's doing. She will either let you know or tell you she's not ready, etc.  Just accept her answer.  It's not that complicated.