They are notorious for the gauges being incorrect due to the sending unit as mentioned. Change the sending unit for good measure, test with a mechanical.
If the oil pressure really is low, go with some additives as mentioned and ride out. Fix the leaks cause JR probably won’t check the oil. I’d say the motor could easily outlive your sons teenage years considering the chances of it getting crashed (no offense).
With that mileage it would suck to replace the motor only to lose the tranny 3 months later, and that can happen when and old tranny gets a fresh powerful motor. I’d just fix it a little as some bonding time, learning from YouTube and drive it till the wheels fall off. Then you can sell it here for parts.
