Brian and Justin as guaridans for Claire's sons

[meta1960]

I'm looking for a story where Brian gets a visit from Joan and ask him to take John and Peter because social service took the boys from Claire. On B/J wedding day they moved in in Britin and soon they have new friends named Eric and Erica and another boy, I don't remember the name. In the progress Brian found out that he has another older sister, I think her name is Cathy and her husband is Craig. Ring a bell?

FOUND IT, link is in the comments