Three siblings who were physically abused as children now as adults reconnect because the brother has the memories of what happened and he helps his sister recover from mental illness brought on by the abuse. One scene is a flashback of the three as children holding hands as they jump into a body of water to escape the reality of their shared abuse.
I am betting that is “Prince of Tides.”
I forgot to add the link: https://www.imdb.com/title/tt0102713/?ref_=fn_al_tt_1