Ask HN: Storing financials/sensitive information on a VPS?

I want to build my wife and I a front-end for managing our financials, registrations, insurances etc.

I have a decent system to scan all relevant documents and make them available on Google Drive. But since I'm the one sorting and filing, it doesn't scale so well when I need to share info with other family members.

What considerations should be taken into account to making sensitive information available over the web on a small Digital Ocean droplet?