I'm 
that I know this but here goes...
Kathy is married to Rick Hilton (of the hotel chain). He is in real estate and employed Mauricio for a while, until he branched out on his own. They have 4 kids: Paris, Nicky, Conrad and Barron. One of those boys, not sure which, is currently under house arrest I think, for a hideous scene he caused while off his head on something on a transatlantic flight last year, where he told all the cabin crew they were peasants and he would get them fired. He had to be restrained. Also, I think he was involved in a hit & run or a speeding police chase or something not long ago. Whatever, he's a brat. Nicky recently married a Rothschild. And we've all heard about Paris.
Monty is heir to a supermarket chain, but not sure how wealthy he is personally. He fathered Kim's first daughter. He's a bit of a free spirit and has always come and gone throughout Kim's life but they have stayed on good terms. He has another daughter with his second wife.
Kim then married Gregg Davis, who is a billionaire and fathered her next two children, Whitney and Chad. Chad also has mental health issues and has been hospitalised in the last year or so due to this. Kim reportedly receives a massive monthly alimony (or maybe child support, but both kids are grown now so ???) from him until she remarries (although she hasn't yet done so - just lived with people).
She was then in a relationship with John Jackson, father of Kimberly. They never married, but are still on good terms I think. He has more children with his current wife I think.
Next, she was in a relationship (engaged) to someone called John Collet, who was shot in the head outside a shopping mall whilst on the phone to her. He was involved in some sort of fraud I think, and his murder was supposedly by a paid hit-man.She has never got over this, apparently.
And then there's Ken, the bull-mastiff (according to Brandi). He was universally disliked by all her family (except possibly Chad, who was going out with his daughter). Rumour had it he was her drug dealer. Allegedly.
She is currently single. good job too.