Single male, no kids, only child, 30 years old.
1. Buy an NFL team and be CEO as my full-time job. I'd probably wait 5-10 years to give myself some free time.
2. Build a very nice house for my parents with a suite for myself. Room for future caretakers that my dad will need due to ongoing, unavoidable health problems.
3. Clear all debt for family members, maybe buy a few people houses, help with renovations, etc.
4. Invest in businesses in the industry of their choice for many of those family members to operate. After they are paid a generous salary, profits would be split with their share going to buy the business from me in a 15-20 year time frame. At least one of these would be a farm, probably 2-3. Each of these businesses would have a board of directors composed of uncles/aunts with relevant business experience.
5. Build a massive vacation home on a ski resort in Colorado or Utah with enough room for all of my extended family(cousins, aunts, uncles, grandparents) to sleep comfortably. This would be used for an extended family vacation every winter.
6. Various philanthropy, I haven't thought through the specifics.
7. For investments I would primarily invest in low risk investments. I would probably devote about 1 billion for more aggressive investments in tech startups because I understand the tech industry better than any other industry.
A couple of notes, most of my family have decent jobs, own houses, and many own small businesses already. No multi-millionaires or anything, but almost everyone is doing okay.
Overall I would make sure that everyone in my family would have the opportunity to live upper-middle class lifestyles, but probably not a ton more than that, except for one of my cousins who I'm really tight with.