I did the module last year and found it pretty manageable, but I have done A-level biology and I'm a pure biology student. The nurses/midwives/people doing it to get on another course with little scientific background did struggle. The workload is fairly high, there is a lot in those three books. But it is certainly not impossible and if you have the books now definitely get reading before the module starts in October. If you don't have the books then have a look at GCSE Bitesize to recap basic biology and chemistry and the Khan Academy for some more complex biology. There also might be some useful module materials on Open Learn. I can understand why the fail rate is high for this course, because it is full on if you have zero scientific grounding, but you do have enough time to change that to do well on the course still.
There are Facebook groups each year. I wouldn't bother on here, there are so few of us. But I imagine the 2017 entry FB group is already going and people are always supportive, there are restrictions about what you can post but some people have even managed to arrange study groups from the FB groups. Also, have a look into SRW. I'm yet to see SK277 supported there, but it is an OU revision weekend so if its there it is definitely worth attending for revision help.
All module materials are included in the price of the course, this may or may not include textbooks because the OU are currently phasing out printed materials (especially in biology over the other sciences it seems), but the module information will tell you whether you'll get books or whether it is all online.