Purgatory and Pentecost: purifying fire

I once knew a Roman Catholic fellow who was terrified of purgatory. It really haunted him. He had done something genuinely awful that was burned into in his thoughts: he had blamed one of his own mistakes on someone else, who had lost her job as a result. He described -- fearfully -- the cost of purification that he expected to endure in purgatory, and he quoted the Bible to the effect that everything would be purified by fire. He could make himself unsteady contemplating the horrors of purgatory.

At the time I wasn't really sure what to say. I think I looked up the verse in question and mentioned that the Bible also said anything that couldn't endure fire would be purified by water, hoping that Numbers 31:23 was the passage he was quoting. I knew my belief "there's no such thing as purgatory" would not get me far with him; he knew he needed purifying and to him that was all there was to say on the topic of whether there is such a place as purgatory. But I write this in the hopes that anyone else in the same situation might consider it:

If we are purified by fire, consider that the apostles met with purifying fire too. It was at Pentecost. The Holy Spirit descended on them as tongues of fire. Yet they were not hurt. God's purification is not necessarily different than Pentecost, the baptism of the Holy Spirit and fire that we were promised that Jesus brings.