I am in the process of starting my business and I have a relative who would like to invest now, and then again later (probably on a larger scale) if we expand. He would like to be part of the business for as long as it's running, but is not requesting to have a voice in any decisions. I guess he would be a silent partner? He says we don't have to formally name his as an owner, so we will keep it as a sole proprietorship for now. My question is: do I need to do anything legally regarding this investment? Do we need to draw up a contract, such as an angel investor contract? We would like to keep this informal, but I don't want to get into any legal problems later. Does anyone have any experience with this?