If you've ever seen a digitally-restored movie, showing before and after frames, you know what I mean. I grew up watching reruns of old movies that were scratched, the color had faded, etc. And when DVDs were introduced, and the process of digital restoration came about, I was amazed. I guess I had never given it much thought, but blurry images, poor color, pops and scratches on the old film I just took for granted. But that isn't how it looked when it was originally made.
Adobe Photoshop Elements has a wonderful tool called simply "Enhance". I was nervous at first to try "Auto Color Correction" but many times it has a spectacular result. It has to be used in conjugation with "Auto Levels" and "Auto Contrast" I have found. I do these individually, and if the results are harsh, I undo. "Sharpen" almost always gives a terrible "fake" look to an old photo, so I rarely use it unless I am trying to "tease" out some detail. I also use the burn and dodge tools, again, with restraint. If the image looks "Photoshopped", you have ruined it. It should look the way the image looked when it was brand new in 1970.
A little research will tell you that an image that has "sepia tone" is inappropriate for the 1930s. And even though your parents' photos from the 1970s have acquired that "antique" Instagram look, those photos didn't look like that originally. The colors were bright and clear, much like a new car from the 1970s. Of course, over the years, your parents' 1970 Torino has probably gotten pretty faded, too. But I want to see what it looked like new!
Over-restoration is pretty terrible, so if you really don't know what you are doing, leave the Photoshop filters alone. But a beautiful digital restoration to a photo, like a beautiful restoration to a car, is a thing of beauty. It takes care and knowledge. If you care, and can acquire the knowledge, you can do it.