In the third episode of The Boys Season 4, we learned that Frenchie is homosexual. It was revealed in the previous episode that Frenchie was to blame for Colin's family's demise. At first, we were unaware that Frenchie and Colin had such a lengthy past, and it is clear that Colin is unaware of it as well. The past of Frenchie and Colin was disclosed in Episode 3, but the reason Frenchie killed his family was left unseen. The reason Frenchie murdered Colin's family was made clear to us in Season 4 Episode 4.
For Nina Namenko, Frenchie killed Colin's family.
Colin also reveals to us that his mother was pursuing a Russian mafia lady in a moment when he tells Frenchie that his mother was a Federal Judge who had prosecuted violent crimes. Without a sure, this is Nina Namenko, Frenchie's previous boss.
It seems that as Colin's mother became more intimate with Nina, she enlisted Frenchie to break into Colin's home and murder his mother. Thus, For Nina, Frenchie slaughtered Colin's mother and his whole family. As we already know, Frenchie was recruited by Nina as an assassin.
But ever since he eventually admitted to Colin that he was the one who murdered his family, it seems that he is engulfed in remorse and shame for what he did. Following this, Colin attempts to kill Frenchie for murdering his family, but he is stopped in his tracks.
In what direction is their relationship going? I suppose the fifth episode of The Boys will reveal everything. Stay tuned till then!