If you have access to a lawyer regarding your joint business, contact him to work with the executor. I'm a retired litigator but I would not give you any advice beyond this because as noted by u/zemere most of the people giving legal advice in response to your post do not even know what state you and the decedent live/lived in. Most real lawyers will look at this post and spot issues and have questions. Not answers.
If you have access to a lawyer regarding your joint business, contact him to work with the executor. I'm a retired litigator but I would not give you any advice beyond this because as noted by u/zemere most of the people giving legal advice in response to your post do not even know what state you and the decedent live/lived in. Most real lawyers will look at this post and spot issues and have questions. Not answers.