A billion is dangerous, but even smaller amounts like paying off other people's houses could be dangerous for them too. It's a huge change.

I know a guy who inherited a house. He was basically able to live rent free for the rest of his life if he had been smart about it. However he has some issues and those were only magnified by his lack of obligations. He's now out of a job, unemployable due to lack of education and experience and might now be forced to sell the house, because creditors and taxes are coming for everything he owns. The house is also worthless by now, because he hasn't managed the upkeep.

Eventually, when he sells the house at whatever it's worth and whether he does it voluntary or not, he'll burn through that money too. He's not eligible for social security as he owns too much. If it had not been for the house, he could have been helped by either by the health care system to get sorted out and get a job or by getting an early sickness retirement scheme if he was diagnosed as such. As of now, he can only wait until he's poor enough again.

Anyway, I'd probably give my family and friends monthly instalments instead of removing their obligations with a lump sum, and also on the clear condition that I can choose to stop it at any time.