Door openers are easy peasy to install. In my building it was done in an afternoon. A heavy door may have to be changed to be compatible with the opener; our building's front doors were already lightweight enough that the motor could handle them.

I googled a bit and found the Massachusetts Office on Disability, which seems to be a state government department that makes sure regulations etc. are followed and also seems to do some advocacy for citizens. Their client services page might be the way to contact someone and ask what your rights are, and in particular you could say that you're worried about how your landlord would react if you asked for this to be done.