Stepgrandpa Died. Having Trouble With Family And Inheritance Issues

My stepgrandpa died and he had multiple houses and businesses. My grandma is super old and is trusting everyone around her. While my mom is the closest to her, my grandma has a brother as well that's in a different state. My stepgrandpa had a business partner as well. My mom is gullible and believes anything they say, and the business partner decided to bring a lawyer on his own , not listening to me or my father that these people don't care about us and want benefits for their own. They're both from the same country as well. The other day the Business partner was able to access my stepgrandpa's laptop and bank accounts to pay for his funeral. When i asked him how did he access the laptop and what's the password, he ignored the question. I find that person shady.

I'm worried about multiple things: 1. can that business partner and his lawyer play some tricks to gain the business and/or take some more money from my stepgrandpa.

1. My stepgrandpa and the business partner and the lawyer are all from greece. I don't know if he has laundred money to greece, but the business partner had a random trip to greece for a week intantly a month after he died.

My grandma's brother ( which my mom has only talked to 3 times in her entire life) is saying that he trusts the business partner guy and the lawyer as well. I don't know if they have any plans behind closed doors or if i'm overthinking it.

P.S: there were no wills or trusts written.