You posted the link where the Cardinal says:- 
"And so, families have to find a way to stay CLOSE to a child in this situation — to a son or grandson, or whatever it may be — in order to try to draw the person away from a relationship which is disordered."
And again:-
"And so it’s important to stay [as] CLOSE as one can. But, that particular form of relationship should not be imposed upon family members, and especially upon impressionable children. And I urge parents or grandparents — whoever it may be — to be very, very prudent in this matter and not to scandalize their children or grandchildren."
How do you get the impression from these words that the Cardinal is advocating 'shunning' children or grandchildren?
Look at this another way. The son or daughter would be aware of the parents belief that homosexuality was gravely sinful so would they not refrain from bringing their partner with them to such gatherings out of respect for their parents and family?