As mentioned by foggy, jazz harmony (which I frankly suck at) or counterpoint are both the things which will give a formal understanding of this sort of thing.
That said I picked up a lot of it more from playing regularly with people who are much better than me at music. In the end if you immerse yourself in music that uses these ideas more regularly you start encountering strange chord notations and seeing patterns in why they are as they are. Finally it isn’t really a prescriptive thing, there will always be many ways to write the same chord, and it will usually be much of a muchness what is written vs what you actually play.
In the case above I’d probably always write it as a D because for someone trying to learn it quickly they’ll know what a D is more instinctively than a weird augmented minor.
I mean, just give them money?
Put it this way: getting a job is just one of many challenges facing homeless people.
For example, if you get a job but are already living absolutely hand-to-mouth, can you actually afford to have that first month of work with no money coming in on a day by day basis. If you cannot afford to even eat how will you make it to that first paycheck?
Even if you do, where will your job put that money? Many, many homeless people do not have a bank account, and what do you need to open a bank account? A home address and ID!
Were you fortunate enough to become homeless with a copy of your birth certificate or other form of ID? If not oh that’s not a problem sir, it’ll cost you £35, and then it’ll arrive by recorded delivery to your home address. Where was that again?
Pretty much no person is homeless by choice. Most are there by a combination of bad luck, violence, a lack of a social security net, mental illness, and many many other factors. Very few people would choose a life of danger and unprovoked violence. You wouldn’t want to be without a home, they don’t want to be without a home for the exact same reasons.
So in conclusion, it is the very basics of human decency to feel bad for them. I would urge you to go further and try to help them, whether that be by direct contribution, by volunteering, by donating to a housing charity, or something else.