I think you'd be better off with a standalone audio recorder. if you're going to be shooting with your iphone, then the mic will only record what is near the iphone, not necessarily what you want to record. if you get a standalone recorder like a zoom h1n you can put the recorder someplace much closer to the actor. also you could get a cheap lav and put it on your actor and connect it to their phone and have them record their dialog in their pocket while shooting.

Rode LAV mic is the best small mic I've found, but the clipping is probably going to happen without some way to control gain. Otherwise the phone/GoPro is trying to autobalance all the time.

https://www.amazon.com/gp/product/B00EO4A7L0/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I've recorded motorcycle content with the Rode LAV mic plugged into a small handheld Zoom recorder. Way better audio than anything a GoPro or phone would ever record for me. Keep meaning to mic up the car for a track day, but it falls behind on the list every time. 😄

gotcha. At that price range, camcorders are more or less gonna be the same feature wise so I'd say just let your dad pick whichever looks the best to him. As for audio, I'd suggest something like the Rode SmartLav+, not top of the line but not bargain bin level either. I'm specifically recommending a mic that connects to your phone since I think it can sometimes be a bit of a logistical problem if you need to stay close to your camera and having a wire someone can trip or get snagged on running between the speaker and the camera. There are cheaper mics out there that might work (I ran my first wedding using a some $7 thing off ebay) but I wouldn't recommend it. I think it's worth the extra money to get a proper/reliable mic that is just going to work. hope that helps!