A power of attorney for financial matters does not give a person the right to comingle funds. You sister-in-law needs to to keep your mother-in-law's funds separate from her own, especially the social security funds. The money belongs to your mother-in-law and should be used to pay for her expenses, debts, etc. Whether or not that includes the care you provide will depend upon the specific facts.
Answered on Apr 10th, 2014 at 12:32 PM