TL;DR Your dad's PHP is no longer the current PHP. The language itself has been thoroughly modernized, made more consistent, bug free and performant. There is nothing better than a piece of software that keeps getting improved decade after decade borne out of real developer needs and experience.

- Type annotations are integrated and work well with PHP now. This results in a kind of scripty Java OOP that is more succinct and type checked ! (it is possible to write PHP without types when you want metaprogramming features also)

- Many inconsistencies in the design of the language (OOP, function naming etc.) have been resolved/smoothed out

- The language recognises the inherent problems with `null` and allows you to make type annotations that rule out null. This is my smell test for a language BTW -- golang for instance does not seem to have a good story for null.

- PHP Language developers have been really good about increasing performance year after year

- Lots of software like web frameworks and CMSes continue to be based on PHP

And -- the greatest part of the design -- PHP remains the best example of the "shared nothing" architecture. An architecture that allows you to scale your application easily.