Looks like you need to disconnect the father next. This will also disconnect him from the brother automatically. Then create or connect with the actual parents.
Please also add to the biography and create complete citations for this profile. There is info in the help pages on how to create citations from Ancestry. There's also a browser extension that will help with this. Find the help pages under the Help drop down menu. And find the info on the extension on the apps page under the Find drop down menu.
Don't worry, mistakes happen and this one, like most can be easily fixed.
Come back here to the forum if you have any other questions.