I'd put Campus solidly in a B class neighborhood with some parts bordering A class, just looking at property values.If you want C/D , hop over 71 and look at Linden.

If I make 9% in the market I'm doing a great job, but if I make -9% I'm screwed, so that seems like a huge gamble compared to a guaranteed ROI. 

Things like that should be pretty minimal in the grand scheme.That's assuming the HOA in question has good financials and an adequate reserve fund, so if they do suddenly find out they need a new roof, they don't have to hit the owners with a big assessment, but that's a whole topic by itself.The real gamble is how long this guy is going to be around.  

But it's okay, because if his gambling winnings aren't sufficient to pay the rent his family will give him money. 

But it feels a lot like gambling to me, and I'm a terrible gambler. :)I hope you'll take this in the spirit intended, but it sounds like you are trying to keep all your options open.

Mainly because I am not good at it, and feel it is just gambling.

The guide covers organizations that can help with vacant lot use, recommendations for fences/borders, plant recommendations, ideas for neighborhood pathways, food forests, outdoor classrooms, community gardens, orchards, and vineyards. 

Detroit has properties worth 250K + (Indian Woods / Palmer Woods / Downtown) and Detroit has properties worth less then 10K and if you do not know where these borders are because you do not live or have not spent a significant amount of time in Detroit you are guaranteeing yourself a hardship.

She won't be able to keep up with his spending, or gambling problem or whatever it is.  

I think maintaining open lines of communication with the tenant and family will help the situation tremendously.You're taking a gamble, but it's one I would probably take too.