Further proof of your lack of knowledge on the subject. I've probably been in a bookies twice in the last 5 years, and both times it was to watch a race rather than place a bet. I'd guess that 99% of those who go in betting shops are the mugs, they are the ones who subsidise the many online offers that gives the shrewdies a decent chance of beating the odds.
It will be a pleasant surprise to my family rather than a shock when I'm gone, but at my age it does remind me that I should leave them a list of all my accounts and passwords. The golden rule of betting - never bet more than you can afford to lose - was rammed home to me as a 14 year old when my whole week's pocket money ended up with the bookies, that week without sweets taught me a valuable lesson.
I'm only a small stakes gambler, if I went in with large amounts it would actually matter and spoil the fun. I enjoy treating it as a bit of a game, me v the bookies, and there are not many hobbies that leave you a few quid better off.
Sorry to say it, but your dad sounds like a mug punter, and I think you are the one missing the point. Going into the bookies and betting with them over the phone is a sure fire way to lose money. The bookies make a guaranteed profit because they build in a margin to cover their costs and a bit more. For every £100 staked, they pay around £90 back. In the old days of 10% betting tax on top of the bookies margins, it was almost impossible to beat them. That only changed when betting went online, and what they make from the mug punters allows them to make some pretty spectacular offers. The advent of things like 'best odds guaranteed' and 'money back if your selection finishes second to the favourite' means that if you are selective it's really not that difficult to make a few quid.