I have four Pro, two Swift and one B17. One thing I learned is the softer the saddle, the more it pushes up at my tender parts. A really firm Brooks keeps my weight on the sitzbones and off the soft parts. This lets me slide around for comfort and riding position. This is what makes a Brooks a Brooks and not a mattress. Nothing macho here. The notion of a Brooks needing to be broken in runs counter to my experience, but they do get more comfortable with mileage. My oldest Pro i bought new in '73 and is still hard and comfortable after many thousands. For me, the B17 is too soft right out of the box and I pray it doesn't get softer. But, every rider is different.

If you buy your dad a Brooks, try to match the saddle to the rider stance on the bike... Wider saddles for higher bars, narrower and longer for more aggressive position with the bars lower.
Just one opinion of many.