To sit in the shade on a fine day and look upon verdure is the most perfect refreshment.
Sitting in the shade is one of my favorite things to do in the summer. Walking in the shade is great too. About ten years ago, we lived in Bloomington, Indiana a town blessed with shade trees. There was a park near the end of our street and I spent many summer evenings there with our son, who enjoyed the parks playgrounds and its basketball court. Sometimes, I would get the chance to walk along the path that circled the park, winding into and out of sun and shade, enjoying the difference between the heat of the sun and the cool of the shade. Shade makes summer bearable. If you, or your parents, are blessed with a yard with some shade trees, take some time to sit under one of them and sip some iced tea - or another cool beverage - it can make a wonderful pause in a hot day.
You may have heard about the benefits of shade trees, particularly in urban areas. I was quite amazed, however, to read about what a difference shade can make in lessening the urban heat island effect you may have been hearing about during this particularly hot summer. Perhaps, your parent(s) live in one of those heated urban centers. If so, don't worry. There's probably a park somewhere nearby, where you can enjoy some free shade. North American and European cities are particularly generous with park space, but countries around the world also have their shady nooks. If your parent(s) is able to walk comfortably for a block or two, you can walk there during the early morning or evening and enjoy the benefits of exercise and relief from the heat. Otherwise, you may need to drive. Either way, spend some time enjoying fresh air and green space. Both can lift the spirits. If you're really lucky, you or your parent(s) will live near a park with water, like the one in this picture. Nothing beats a cool breeze off the water.
As far as the iced tea, make it however you usually do. Making sun tea can be fun, if you have the time and the inclination. My mother-in-law used to enjoy doing this in the summer and it was delicious iced tea - never bitter. In some parts of America, people live on iced tea in the summer. In the South, they call it sweet tea or cold tea. My mother grew up in Kentucky and I've enjoyed many a glass of cold tea. In fact, I was 16 before I realized that you could drink tea hot. Seriously.
The point of all of these tips, is to take the time to pause in the middle of a busy day and find time to relax, enjoy the simple pleasures of summer, and spend "quality" time with your parent(s). These will be the memories you'll be happy to have when your parent(s) are gone. Many of these tips are aimed at building memories for the future, kind of the way that squirrels bury nuts or a bride builds a hope chest (do brides still do that?) Here is a thoughtful article about Quality Time with Elderly Parents. And, even though it may seem that you simply don't have the time or the energy to pause long enough for sitting on a park bench or sipping iced tea, it will be time well spent.