sadly, Pelosi, Kennedys, Biden, ORielly among many others claim the catholic faith but do not adhere at all to its teachings on much of anything. On this I totally agree. I do disagree on the sin issue. Check 1 John Chapt 5 Vs 16 and 17.
If this be true, there is deadly, or mortal sin. If that be the case, then there is sin that can seperate you from God, and our brother can commit it.
A Baptist would say that all sin is mortal. The only issue is whether God can and will forgive it. Without Christ, it won’t be forgiven no matter small it is in our eyes. With Christ, it is forgiven, no matter how large.