Paul's family couldn't seem more homey if they came to us straight out of Berenstain Bear country (although that would make for a very different movie—The Berenstain Bears In No Man's Land, anyone?).
We have the protective mother, the proud father, and the sweet lil' sis, Anna. Each supports Paul, and they try their best. They really do. But like Kantorek, Himmelstoss, and the other townsfolk, their ignorance of the true horrors of the Western Front leaves them unable to understand Paul's suffering…or how the war has disillusioned him.
Let's start with Paul's father. He's one proud papa and sees his son as one of Germany's heroes—"an iron youth of the fatherland," to borrow Kantorek's words.
This is made evident by his introduction of Paul to his friends:
"We're behind the lines, but we know how to honor the soldier who goes on in spite of blood and death. Gentlemen, my son."
Under typical circumstances it'd be great that Paul's father is so proud of his son. Unfortunately, Paul's father's pride comes from ignorance.
When Paul tries to tell the gentlemen that "the war isn't the way it looks back here," Paul's father doesn't follow up on that. He's too busy recommending that the German forces break through Flanders and on to Paris. Paul's father sees his son as a hero and the war effort as a glorious adventure—he can't see any other reality, even when it's right in front of him.
Unable to grasp the truth of Paul's experiences—likely because he hasn't bothered to ask or listen—his pride in his son really should instead be mounting concern for his wellbeing.
Paul's mother has a similar problem, but in reverse. Instead of seeing her son as a glorious soldier, she still sees him as a boy. This is evident by her concerns. Rather than worry about him being shot, she worries that he isn't eating enough or that he should be "on [his] guard against the women out there."
Yeah, mom. The real problem out in the trenches is that there are too many pretty girls. What if precious little Paul ends up dating a floozy?
Now, to be fair to Mrs. Bäumer, it's possible that she understands the true dangers her son faces but is simply unable to talk about them. She tells Paul,
"I'll pray for you every day. And if you could get a job that's not quite so dangerous…"
The way she trails off could suggest that she's well aware of the dangers but can't bring herself to give them voice because they scare her. So she reverts to her motherly concerns from Paul's youth, the ones she has a handle on after years of practice. (Stay away from girls who wear skirts that show off the calf, Paul.)
Ultimately, Paul's family's inability to comprehend Paul's emotional state leads him back to the people who do—his comrades on the front lines.