Drew,I actually live in Kansas City and work as a property manager as well as an active investor.

I will try and seek out an attorney as it sounds like this is the best place to start. 

As Andreas mentioned, it's good policy to outsource your debt collection activities to licensed 3rd parties to reduce risk and stay compliant with rules and regs.

The other general question I'm seeking advice on is just if anyone has opinions in general for the Boston area on the best use of my funds at this point - a little vague I know, and while my agent is trying to give me the best advice he knows to (and he works with other investors), I just want to get some different perspectives because he seems fairly against anything needing any renovation.

In my current role at my 9-5 job, I can't hold an active license but this will be good info for me to keep in the back of my mind for down the road.

I'm seeking multifamily homes and have a couple in mind I'd like more info on. 

I am currently in the process of seeking out options for financing the property of my liking but my credit score right now isn't the best.

I'm working on getting active listings built up but am admittedly having trouble.

I have used Single Source only for my purchases on SFRs but not for any legal activities related to your brother's situation.

If they continue to refuse I would seek some legal advice from an attorney.