Encourage them to drink plenty of water to ensure they stay hydrated.
You can add light-weight and breathable clothes to the wardrobe.
Keep their living space cool with air conditioners or coolers.
Install window shades or curtains in their rooms to avoid direct sunlight.
Advise them to stay indoors during peak heat hours.
Check on them regularly especially if they have health conditions to ensure their safety.
Provide cool baths or wet towels to help them stay cool and comfortable.
Advise them against performing intense workouts.
Incorporate fruits and vegetables into their diet.
Keep an emergency plan ready in case they suffer from heat stroke.