@Mike Lambert The main thing is you cannot count on currency fluctuations like that. 

The price of labor also fluctuates, though not as much as materials.

If you're going to really win this thing, I think you're gonna have to work on the sales price because depending on how firm he is on that $200k and how long he's sat at that price, everyone's been running the same analysis, give or take fluctuations in rehab costs.

The more tech names that drop like Amazon the more they fluctuate.

Especially when you consider the risk of fluctuation with stocks I would add.

(an investor who only buys and sells in US markets has very little exposure to foreign exchange, so the fluctuation of the US Dollar may go unnoticed to you.)Back to my point... the value of the US Dollar rises and falls, but the paper it is printed on wears out and must eventually be taken out of circulation and replaced by another bill.

I’m guessing if yes, the logic is that many self-directed investments don’t fluctuate much like investments in the stock market do daily.

I would ask how long they have been working as a foster parent and how much their income fluctuates from year to year. 

You didn't mention it but if you plan on leaving California in any time under 5 years, then buying in a market that has large fluctuations could leave you trapped and with less options for an exit. 

The rising rates can cause some lenders potential harm if not managed correctly though, so this market fluctuation means it's even more important to underwrite the hard money lender that you invest with to make sure they aren't in a bad position.Good luck!