It could be that you need a little help from others to get ready for the viva. Help with thinking and talking; questions about process and experience; maybe even proofreading or practical on-the-day logistics.
You have to defend your work solo, but there really are lots of ways others can help you prepare. Get clear in your mind about what you need, ask and explain why (if you need to), and be prepared to compromise.
It could also be the case that you see a friend who needs help. A candidate who needs someone to talk to; a colleague who needs someone to listen; a friend who has a problem that they can’t see past.
It’s OK to ask for help when you need it; it’s good to offer help when you can.