Brake emergency

Well father-in-law wants another crack at it bless his heart.
Front wheels seem to act appropriate. Meaning they stop when I hit the brakes. Or at least I cant physically turn the tire if the brake pedal is pushed.
The rear however are too loose. We did the grease at the spaces on the backing place that contact the shoe.
This car isn't coming back from the dead, as I bought it and it had been driven. Just not taken care of properly.
I have ordered all new hoses, and also all new parking brake cables.

It is difficult for me to know what to expect with a single chamber system. Seeing as all the cars I have ever driven have been newer.
But I do expect that if I am driving 30 mpg and slam the brake all the way down, that I should either skid or stop and/or the wheels should stop spinning. Is that correct?
Will keep you guys posted.