Actual Earnings Threshold and health condition

Hi bit of a complicated one for my friend. She has a term time job and had to reduce her hours a few months ago due to health issues and edging on the side of a break down. Her work reduced her hours under a reasonable adjustment. So now she works 19.5hrs a week. She is just under the AET so is being called in every 4 weeks to try and get above it. However from looking at it she is above the WCA earnings limit for an assessment to consider an AET exemption. She only has to earn £50 a month more to meet the AET but the pressure this is causing is making her health worse. She doesnt get LCW or LCWRA or pip. But cant be referred for a WCA due to her earnings so therefore cant be looked at for an exemption for the AET. What can she do? She has a long history of mental health and had to reduce her hours to cope and keep her job (as she has had a lot of sickness absence). Things are a bit more stable now shes doing one less day a week. But increasing it through pressure is only going to result in how things were before and probably losing her job. She also has a vulnerable teenage child (15) who is currently under CAMHs and with the local authority being involved as her child has missed a lot of school. The school did threaten prison so she has had a lot to contend with caring wise. Her child doesnt get DLA or anything but suffers with severe anxiety and emotional based school avoidance. So she cant apply for the carers element due to not getting DLA. What are the options? Shes a single mum and only gets UC. To also add more complications it will mean she has to pay more council tax to and get less rent help due to being asked to earn and extra £50 a month. Shes already in a lot of debt and has nearly lost her house a few times. Thanks