Tempting, but "Services start at $1,750" --- I could buy multiple replacements for that, or make a downpayment on the Seiko Grandmaster or GPS which I want...
That said, I'll keep it in mind and maybe if I come across a windfall will apply thusly....
For a Seiko, I'll also recommend https://www.theseikologist.com/. As his name suggests, he specializes in Seikos and has a large stock of vintage Seiko parts which are hard to source. Though, it's still not cheap. I have a broken Seiko chronograph from the 70s and he quoted $500 to just do the watch equivalent of a tune up. He can't give a better estimate without opening it up, which is understandable.
If it isn't a hardship, I do recommend fixing your dad's watch. Sentimental pieces are always special.