I think it's a gamble.

If it's an experiment for him, you're taking a bit of a gamble, but as in all risks one that could payoff.

Investing is gambling...it's not if you do it right.  

Orion is right on, its great to have the motivation and some cash to do something, but one bad investment will eat that right up. seems like you are in the time in your life when the gambles can be made and live minimally. do it now, take the risks now, but make sure they are calculated. 

I guess it's always a gamble to do it last minutes. 

If you assume you'll never have these big, unpredictable expenses you'll be in trouble if they to happen.In general I think investing is like gambling. 

If the property has zero equity, likely due to some senior lien holder like a mortgage, then putting the repairs into the property to only receive say $1,000 in rent each month is a pretty high gamble.  

And the cost of making that gamble is much different also.

It is a gamble but putting 5k in the bank a year adds up quick and easly covers new roof etc.

Let's gamble!