I checked up on this (for various reasons!)
After 28 years together, she would definitely have a claim against you if your dad did not make adequate provision for her in his will and you are the only other beneficiary.
I don't think the fact her first husband left her 'well cared for' is relevant. After 28 years with your dad, don't you think she is entitled to something from his estate?
(I'm not saying the amount she took is right or the way in which she took it.)
After 28 years together, she would definitely have a claim against you if your dad did not make adequate provision for her in his will and you are the only other beneficiary.
I don't think the fact her first husband left her 'well cared for' is relevant. After 28 years with your dad, don't you think she is entitled to something from his estate?
(I'm not saying the amount she took is right or the way in which she took it.)