OP I would just take a step back and not be over invested in the current behaviour. My DM looked after my DC (involving taking time off her job and swopping homes for two days and a night because she lived in London where I needed to be for long hours) and my DC associated her at that point with me leaving and were difficult. She didn't panic or cry or let them know how distressed she was. She didn't try to bribe them to love her. Two years later she was their favourite person because she was interesting, interested in them and kind and thoughtful.
Kate Garroway-Care at home costs