Hi, Noted the history about your friend having well controlled Tuberculosis, Epilepsy and asthma, gets weakness and lightheaded on working in hot weather. Surely the cause is working in hot atmosphere as this drains the energy due to excessive sweating and she is already having three major illnesses. Her Mother might be asking her to mow the lawn in the form of an exercise as might have been advised by Doctor. Get a confirmation. Surely, it is best to work in shades. Physical activity to a certain amount is helpful for good recovery. Dizziness as you have have mentioned looks to be fatigue and needs supplements like multivitamins, mineral and trace elements. Good protein diet helps a lot. Further management as per the clinical evaluation and investigations. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. T. Chandrakant, General Surgeon