The SPD has rolled over for the CDU in the past on things, but they've also blocked things they thought were important enough to block, so it's really anyone's guess if this go through (I personally wouldn't bet on it, but I'm sure a bunch of dour pessimists will come explain to me that it's a foregone conclusion and I'm naive).
And yes, no idea why the SPD is so on board with this - some measures, like having to provide a medical certificate from the first day of an illness (which in practice means you have to go see a doctor personally on the first day of sickness), are definitely not going to increase the dismal approval ratings of this government. So, for example, if you're prone to migraines, until now you would have simply called in sick for a day, now you have to drag yourself to the doctor, only for them to tell you (after potentially hours of waiting) "oh, you do look very pale and sickly today, you probably do have a migraine, here's the certificate. I assume you already took one or several headache pills? Now please, go home and rest."?!