Legal Question in Business Law in Colorado

You are free to add a member you want to your LLC. What matters is properly determining the percentage of their interest, their role, what happens if there are disputes, and on and on. If this co-owner is purely investing and they are not a co-manager or a voting member, then you have issued securities and that must comply with state and federal securities laws or you run the risk of them getting every penny back and being liable for the violation of state and federal laws.

Essentially, you need to hire a business attorney before you consider having a new member.