Please help with WordPress hack

I’m attempting to help my brother who has a popular blog, https://www.packmentalityblog.com. Someone has hacked into his blog and added a porn link between his header photo and the links in the header.

The site is hosted by GoDaddy and I spent quite a long time with their support this evening and they said the hack is buried within the database and it would take $149 for them to fix it. I actually understand that since the flaw is within WordPress and not their hosting.

If anyone can give some direction, please advise. My brother is battling a malignant brain tumor now so spending that amount of money is not ideal.

By the way, I did see a similar post here in the forums. A post by GoDaddy themselves had a link they said took you to instructions on how to fix the problem. However, when I clicked on that link it took me to a site featuring traffic cameras. Bizarre.

Thank you for any help or guidance.