I didn't think too much of that "doctor" Brooks went to see. He seemed about one step up from Shannon's Dr Moon. That blood thing didn't make any sense. Your blood can only reach a certain point of oxygen saturation. If Brooks actually had an issue with his blood oxygen levels he would be turning blue and dying, not getting cancer.
Say what you will about Heather, I think if there's one thing that she is, it's smart. She is very aware of how she comes off and how she needs to present herself preserve her image. (Yes, I think she can be snooty and uptight but I think she wants to look that way. That's her shtick.) If she is calling Brooks' report a "mockument" then there's something to that. There's no way she would accuse him of faking it unless she had some damned good evidence she was correct.
On a totally different note, I'm pretty sure Tamara is only getting baptized so that she has an excuse to throw a party for herself. Maybe she can hire Ryan to hand her a towel after she gets out of the pool.