I have two daughters, one well and one with a severe disability. My advance directives call for my estate to be divided in half when I die. Half goes outright to the well daughter, and the other half goes to a Special Needs Trust for the disabled daughter. My younger brother is the executor.
The well daughter is extremely bitter and vocal about this--feels that since the disabled daughter is on government benefits (SSI, Medicaid, Section 8 housing), she does not need to receive anything and that everything should go to her, the well daughter. The well daughter is divorced with three children, has a good federal job in law enforcement, and has received approximately $200,000 up front from me over the past ten years. The well daughter flatly refuses to be executor of my will or to have anything to do with helping the disabled daughter after her father and I die. There is no bad blood between them particularly, but the well daughter says she is not a health care worker--not a caregiver--does not want to be involved. They live at opposite ends of the country. My ex-husband has done his estate planning similarly, dividing his estate between well daughter, disabled daughter, and his new wife. Our well daughter refuses to assist her sister with his plans for her, either. (Disabled daughter will receive his military pension and Tricare--obviously going off Medicaid etc. at that time--no comment on whether or not this is a good idea--I have no control over what he does.)
So just my anecdotal two cents worth--be careful, as these situations are fraught with pitfalls--legal, financial, personal.