I'm amazed at what some people can figure out to get rid of a problem, I'm talking about the successful attempts. I was trying to get a gimbal bearing out of a boat. It was at my dads and I worked for a few hours without the proper tools in an attempt to remove it. My dad had told me what to do with makeshift tools to remove it. I went in his house frustrated and he asked if I'd gotten it out. I can't remember what I said but essentially NO. My mom gave me a drink of something and I sat down (really frustrated) and she got me on something else. I didn't even notice my dad go outside. He came back in about 5 minutes later holding the bearing, I have no idea how he did it. Of course he was proud of his accomplishment. Since that day I really started to pay attention to how he did things and learned, I could break an anvil with a feather and he could fix it with almost nothing. He's gone now but every now and then when my son is frustrated trying to do something, I get to act like my dad.
Get him the Milwaukee cordless impact battery powered 1/2" 1400 ft lbs of take off torque. I just got a set impact screw/nut driver and 1/2" drill. That 1/2" drill is stronger than anything I've ever used. The batteries will work in many tools so I plan on getting the impact wrench I mentioned above. I watched a video of a guy trying his out on a large rubber tire loader with about twenty lug nuts. He removed all but the last one and it had been sitting outside for years. They make a 3/4 also, don't know specs on it but air impact is becoming a thing of the past.
Dads are awesome and older dads even more. Tell your dad he's awesome and that contraption he made to loosen that nut looks mighty familiar.