Ted wasn't, but he was the only one left. In-laws were ranked lower on the pecking order than Kennedys, because they weren't true Kennedys. The exception to that is Ethel, because she meshed so well with the Kennedy women. (Who are the polar opposite of Jackie in every way) Ethel's attempts at controlling her kids are best described as tragi-comic and the less said the better TBH. It didn't matter before '68 but it certainly mattered afterwards.
The Kennedy men were always the primary parent, not the women. You can't judge Jack because his kids weren't old enough when he died to make the call, but as I said Jackie raised them as Bouviers and she was the only one with that sort of authority over her kids. Not that she needed it of course. For Ted, and certainly for Bobby that was the case. Dates back to Rose and Joe, Joe was the nurture one, Rose was the nature one, distant, aloof. Whenever something came up it was the father who got petitioned by the kids, not the mother. When the fathers were alive, it was always the fathers who administered either administrative or occasionally physical (mostly Bobby in that regard) punishment.
What does this mean? Little change from OTL, but you still have the Gang of Three running wild. Those were the mischief-makers with criminal records: Bobby Jr., the ringleader, his sidekicks Chris Lawford and Bobby Shriver, and the wannabe (who of course ended up being the victim and dying) David. I wouldn't be surprised if some of them got not just felonies but prison terms. The Bobbies have the willpower to get out of the cycle voluntarily and clean themselves up, as happened in the mid-80s IOTL. Lawford struggled and David didn't have that willpower, so he will certainly die ITTL as well.