The Power will only take effect if she loses mental capacity. Powers can be limited to just health/welfare or just financial but usually they cover both. I will approach this on the basis that she loses capacity and enters a care home
I note that you refer to her as your "business partner".
Where a property is held as joint tenants then should one die then under the law of property the share of the deceased would automatically pass to you.
There would be nothing to stop the Attorney from severing the joint tenancy so that you both have distinct shares and her share would then pass under any Will that she has made or makes.
If she is your business partner this would be quite logical.
The attorneys would have to act in her best interests to protect her investment in the house so she would be liable for half of ,say, any structural type works.
If she made a Will before losing capacity leaving her half of the house to you then you are able to challenge any later Will made that alters that alteration.
I hope this help.s
If there are any further points please reply I will be happy to respond further.