I still have to get an apartment under my name
Firstly you don't really have to do that (can your boyfriend's parents not register you as living at their address), and secondly that will be expensive and tricky (a lot of landlords will simply refuse to register you as living at their apartment because they don't want the tax man to find out that they are renting out their apartment and/or the don't actually have the legal right to rent out their apartment and/or they are worried that you being registered there will give you legal rights over their apartment).
my boyfriend's family is willing to register me as an employee of theirs until I can find work in other terms.
That could be a bit of a pain in the arse for them (they'll need to jump through all the hoops of getting you a work permit: they can't just decide to give you a job, they will first need to advertise the vacancy with the local labour office and then after they have received no applications for the permission they can ask for permission to hire a foreigner). It might be easier if they can just agree (formally) that they will support you while you are in Poland. Or perhaps somebody in the USA can commit to that?