Oh, Lord, don't tell me about tight, selfish old people! OP, please don't feel guilty - unless you are so loaded that you wouldn't have missed the money, it was utterly unreasonable of her to ask or expect it.
Dh had an old aunt (childless, no dementia) who was unbelievably self centred, and tight, despite having plenty of money. I used to call her Queen Midas. She hated the idea of paying for carers, and wouldn't, even when she needed them badly - her neighbours were supposed to help her, 'for love'! She would never have put herself out for anyone else. And most of her neighbours were very elderly themselves and more or less decrepit - I would have them on the phone wailing that they couldn't cope any more.
She never gave a toss about anyone else - would demand dh go and see her when he'd just come off a long night flight after a business trip and was so tired - and it was a 2 hour drive. I said to him once that if he dropped dead from running around after her, all she would say was, 'What about ME? What about my food?" (She was food obsessed).
Eventually dh managed to get her into a care home - what a saga that was! - but she then said that if the care home staff knew she had any money they would find a way to steal it or cheat her. So she insisted on dh paying the fees, and she would pay him back. But getting her to sign those cheques - oh Lord - 'HOW MUCH???' she would screech.
If she'd had a tombstone I would have wanted to put 'HOW MUCH??' on it - it was her favourite cry in later years and was even mentioned at her funeral - someone said it as just as well she didn't know how much it was all costing!