Sander doesn't look much like his father. Jazz does.
Well, here’s the question….is a suicide attempt something the family would keep quiet, or would they use it for more fame and money?
Jeanette to every camera on the planet: All this hatred for Jazz caused her to contemplate suicide.
Jazz has a plethora of meds. He’s not on all that shit cuz he spilled a glass of milk.
There is evidence that something big happened to Jazz between Seasons 6 and 7.
1. He didn't go to Harvard as planned.
2. He gained a ton of weight.
This is the chronology for Harvard:
May '19: Jazz announced going to Harvard (
link)
Oct '19: Jazz says he's delaying Harvard (
link)
In his announcement, he says:
“After careful consideration I have decided to take a break before starting at Harvard. It wasn’t an easy decision but it is the right one for me. These past few years have been so full and busy that I realized I could use some time to refocus and recenter to be the strongest version of myself.”
I don't know how Harvard schedules work, but google says classes for 19-20 started in September, one month before Jazz publicly announces he is taking a year off. We found out, through the show, that he indeed decided for Harvard as planned, but dropped already being there or after he has decided to go and being enrolled and that he failed his semester. There is really no much evidence for him to physically have moved there (besides a visit), so whatever happened, it might not have necessarily happened in Campus. Which means, whatever it was, happened around 19' Aug-Sept-Oct.
August '19
September '19: he's doing 'back to school' ads. (where was this pic taken?)
September too, "taking it step by step"
October '19: Harvard announcement.

It's the same dress and hair as the previous pic. Did he already decide it by then? we don't know. But his cryptic message seems to indicate something wasn't right. Either way, his body was still normal.
Nov '19, he starts to gain weight:
Dec '19

His boobs start to have a life of their own.
Jan '20
Feb '20

He doesn't look that big, so this is probably footage corresponding to S6, when he was decidiing whether going or not to Harvard. By this time, we already knew, but the post says he would have rather go to Pomona. He did go to the campus and might have taken the school backpack picture actually there.
We know Jazz is childish. My take is that he signed up to start classes for 2019-20 fall, and he realised he wasn't happy there so he had a mental breakdown knowing he never had an actual chance of going to the one he wanted to go. Or rather pretended to have one (kids do this all the time.) Either way, it was a consequence for his rejection of Harvard, which was likely real.
We know also that his family cater easily to his tantrums and believe all that nonsense about self-care and mental health in the most basic way. Which means they accepted Jazz' words as fact and never judged him for his decision. Nevertheless, Jazz' lifestyle and consequent weight gain was seen by them as a sign of whatever was going wrong, so that's the reason they were so strict and borderline bullies towards him during S7. Like, "we get you're not feeling well, but all you do is eating and sleeping and that is no right either". They were not wrong, but handled it wrong.
We might not think it's a big deal, but many families don't deal well when one of the children say they wanna delay going to College because they see college as a natural next step in life. And we know the Jennings had very high expectation for their golden girl, specially Jeanette. I can see how the other children could have felt frustrated that they were expected to go to school while Jazz is doing nothing at home except getting fat, hence, their negativity towards him. To me, all of this sounds a bit more reasonable than a suicide attempt, which is also very likely.