Toilet trained for nearly a year - now can't be bothered!

[heledot]

My nearly 4 year old grandaughter has been toilet trained for nearly a year and was happily peeing and pooing in the toilet (she never used a potty). She's also been dry at night for several months. She's dry at nursery.
She's recently started peeing and pooing her pants in the evening and at night. Her mum is taking her to the toilet regularly in the evening but to no avail. When asked why she's started doing this she replies that she can't be bothered to go upstairs!
Any advice?

Have you tried getting her to clean up the mess? So she gets herself changed and cleaned up with baby wipes, cleans up the floor, gets rid of the rubbish, so she hs to take responsibility for it one way or another, and realises that the toilet is much cleaner and quicker?

I'll suggest this to her mum - sounds like it could get a bit messy though! Lol!