No Contact Mom Filled Out Legal Form For Abroad Matter And Mentioning Sending It Off Without My Knowledge, What Can I Do?

Location: North Carolina, USA, as is my mom, but the paperwork is for rejecting my German grandmother's inheritance, she lived and passed away in Germany.

I'm going to do my best to explain all this, but please understand my brain feels like scrambled eggs right now from going through this, if you have questions, ask, if I left out something important, please let me know and I will edit my post to add it.

If this is the wrong place to post this, please let me know.

I went no contact with my mom 5yrs ago, that being said, she has my email address and has emailed me about far less important things.

But for this, she decided to find my address (I've moved since the last time she's seen me), showed up at my house, left a note that I needed to urgently contact her.

To preserve a bit of my privacy, I made a fake Facebook account with my real name to message her and ask what she needed. That's when she told me my grandma died, and that her, my uncle, and my cousin have already rejected the inheritance, I am the last one to do so, they don't know how bad her debts are because nobody has been in contact with her for the last few years.

(Before you attack me, I was brought to the US at 5.5, my dad decided I wasn't allowed to speak German out of fear of being talked about behind his back, and then after he left my mom she just couldn't be bothered to reteach me the language, as a result, my grandma slowly stopped talking to me)

When I asked my mom for the list of information I needed to fill out the paperwork to reject the inheritance, she told me she already had it all filled out for me and ready to be sent off and asked me where my mailbox was, so she could break another law I guess? Haha? The paperwork is everything but signed, the envelope is addressed and was sealed when given to me. I unfortunately panicked and ripped open the envelope because I was genuinely flabbergasted (although I shouldn't be, this is typical behavior for her realistically.)

My question is, is there anything I can do about this legally, or is this just a nothing burger, sucky situation? I ask because having the paperwork mostly filled out, having the envelope addressed and sealed, and mentioning sending the letter, seems like something that should be taken seriously.