Facebook still uses PHP for a lot of templating/page generation, they use a bunch of stuff on the back not least HHVM which was great because it forced/focused the PHP team in a bunch of areas, php7 is a huge I improvement over 5 on just about every metric.

It's not amazing as a language still but it's much much better and the ecosystem has really improved, modern PHP leveraging good composer components is pretty good.

Even some good static analysis tooling these days.