Get SS involved. Sooner rather than later gives everyone breathing space to consider what might be suggested. Sounds like they require a safety assessment if they are leaving things switched on. Mum found Oak Farm Foods or Wiltshire ready made meals useful, straight into the microwave from the freezer. Ordered by phone.
What advice has the Stroke Association given, do they get assessments from the stroke dept at the Hospital? If your parents are involved with a Church, maybe someone would pop in for 'a chat' when they could check what was left on etc.? As *we* age the more stressful issues might become, especially if the wrinkles are resistant to change even if they are aware that they need extra assistance.
MinL was left to deal with her parents, she would get them ready for when her 7 siblings visited so they never became aware of her struggles.