Effect off claiming a SSI beneficiary on their benefit?

I have a friend living with me that is 100% disabled and receiving SSI benefits.  She is convinced that claiming her as a dependent for income tax purposes will adversely impact her SSI benefit amount.  She qualifies as a dependent under the tax code and Social Security rules.  I have tried to explain to her that as a legal dependent under the tax code, SSI will not reduce her benefits for living expenses (e.g., rent/mortgage, utilities, and food).  On the other hand, as I have tried to explain, if she does not appear on my tax returns as a beneficiary, then SSI can access the value of those living expenses as in-kind payments and reduce her benefits accordingly.  Am I correct?  Will her SSI benefit be reduced if she is claimed as a dependent?  If she is not a dependent on my taxes, can she be accessed the value of her living expenses as in-kind payments charged against her SSI?