You cannot do this, Wade. We can't add our name to deeds, deeds are vehicles for transferring ownership, not statements of ownership!
Mom would have to deed the property to the two of you, as joint tenants or tenants in common.
However. Whenever property (or money) is in motion, you risk triggering tax events, and if you have siblings, you really complicate inheritance issues.
The simple way to do this, Wade, is to consult with an estate / trust attorney, and a CPA. It's not really that costly, and it can save you big time major league headaches.
All the best,