After a trying marriage, my mother adopted my daughter (I course with all of the other legalities). My daughtet still lived with me but my
My mother was helping me out with her. She was now receiving benefits from my mom. She has recently passed away and out of good measures I let my step father continue in with the guardianship. My mothers name was the only name mentioned in the paperwork as well as on the new birth certificate. Because of recent events (that proves to us that he may have an altered motive), I have decided to regain guardianship. How do I this? After speaking with the family lawyer he said it should be no problem because I am the mother but how do I go about doing this without getting her benefits cut off? This would also mean removing his name from being the guardian over the funds too.

... my mother adopted my daughter... She has recently passed away and out of good measures I let my step father continue in with the guardianship. ... I have decided to regain guardianship. How do I this? ... This would also mean removing his name from being the guardian over the funds too.

You are mixing apples and oranges. If your mother adopted your daughter, the girl is now, legally, your half-sister. It is unlikely that you can adopt her back.

It looks like, however, you are saying that there is also a guardianship, to protect your daughter/sister's assets. If you can convince the court that your step-father is not properly managing her property, you may have a shot at changing the guardian.