I can only add that with the loss of 6 close friends lately, I understand that life is very short. If "cars" or "driving" is your thing, purchase what you want and don't wait (unless it breaks you financially, of course) . My oldest and closest friend always wanted a Jaguar convertible, and recently had a massive stroke. He worked in engineering all his life, produced a new product and negotiated and was finally approved for commission on any of his designs that he "phone" sells. Things were looking good for his finances. Instead, he stroked out and gone. Never to own his Jaguar or to reap the benefits of his product.
He leaves behind a 9 and 11 year old, plus his wife. I can only guess how much fun the kids would have had with the top down, roaring around town with dad these last few years.
Life is short, cruel and unforgiving. The expectation of being able to do what you want later, is one that we falsely believe. If you are 50 and male, 25% of your male friends will be gone by age 60 and it does not get better from there. Of those friends that survive, another 25% will be somehow disabled.
I hope your dad gets the exact Jag he wants and has the time to enjoy it. BTW, Jags are not numb driving vehicles, like so many Japanese and American cars are.