I find it a bit difficult to read and understand what you wrote. Perhaps you can have a second look and edit a bit.

If it comes to investments... no matter what you invest in it's always a risk and you can't foresay the future. It's not said you will find people who can afford paying the rent.
Another problem is that all costs are yours: leaking roof, broken sink, door, locks, you name it. So more capital is needed to fix it and keep the building in good condition (it's stupid to believe it will be in good condition till the end of time).
The best thing to do is buying something that should be renovated for cheap, next renovate yourself and sell it for more.

@lupega has investment plans (apartment) who knows, he can share his vision.

I wish your brother all the best.