A member of my church is a woman in her early 60s who left the RCC a couple decades ago for Protestantism. About 18 months ago, this woman invited her sister, who is a fairly committed but "ignorant" Catholic, to come to our church. She showed up with her husband - a lapsed Catholic. A few days after their visit, the sister was at home and she fell down some stairs, breaking her leg to the point that she had to have fairly significant surgery. I visited her in the hospital a couple times and then at their home - bringing them some excellent chili on one occasion. That I met with them non-judgmentally, and treated them with love and concern, was so touching to him that he's had both he and his wife (the sister of my church member) in our church every Sunday since then. In the past 7-8 months they've come A LONG way and a few weeks ago I overheard her telling another woman that she "thinks" she's becoming a Presbyterian. That was pretty cool. They're both asking lots of questions, especially in light of our current Reformation series.
It is my policy to "view" RCC adherents in accordance with their level of commitment and knowledge. I've met some who are really knowledgable about what the RCC teaches, they repudiate the Solas, etc. These really are the minority, but with these I view them as definitely unsaved, and I treat them like cultists.
Then there are those who may be committed to attending, they self-identify as Catholics, but they really don't understand what Rome teaches, and frankly, they don't really even understand that there's a difference between what Rome and Protestants teach concerning the Gospel, etc. These I view much more charitably, as "misguided brethren" - not saying that I believe they ARE saved, I'm saying I treat them like people to be taught and corrected and assume the best until they prove recalcitrant. Still, I don't consider them as having been baptized, because again, the sacraments are pointers to the Word, and the RCC doesn't have the Gospel.
A third group of Catholics are nominal only - maybe they were raised in it, but now their only affiliation is when they have a kid and need him baptized, or something like that. These I view and treat as worldlings to be evangelized.
By treating the sister of my member, along with her husband, like those in the 2nd category, I won a hearing and by God's grace they appear to be moving in the right direction.
Just my two cents...