The same queasy global inequality explored in Lukas Moodysson’s 2009 drama Mammoth is evident from the opening frames of Kristof Bilsen’s affecting documentary. Contemplative and slow-burning, Mother is a tale of two mothers who, for very different reasons, are separated from their families.

Pomm is a carer in Thailand for white, wealthy westerners with Alzheimer’s. She cares for her patient Elizabeth generously and around the clock, singing as she cleans her, hugging her and sleep-sharing. “I think of myself if one day I get like this, what will I do?,” wonders Pomm. “Who will take care of me? Will my kids do it? Will they love me?”

Elizabeth can no longer speak but Pomm confides her frustrations and disappointments in her older charge. These disappointments often relate to family. Pomm’s duties and poverty keep her away from her own children who live many hours away with their grandmother.

It’s an odd situation: Pomm’s bonding with strangers is an act of sacrifice for her children. That sacrifice demands that she forego mothering them. Meanwhile, in the Swiss Alps, the family of 57-year-old Maya are planning to bring her to Baan Kamlangchay, the same care centre where Pomm works. Maya’s husband says he would feel terrible if she didn’t get the best possible care. They will return home to Europe without her.

Questions about the ethics of outsourcing care and the vast economic disparity between Thailand and the West are obvious and poignant themes. But Bilsen’s film, which is primarily concerned with the relationship between the carer and the patient, is not judgmental.

A touching tribute to the selflessness and humanity of caregivers, Mother is consistently thought-provoking and sometimes heartbreaking viewing.

On iTunes, Amazon and Google from January 9th