Question: Does the Greek text of 2 Tim. 1:16-18 imply that Onesiphorus had already been dead by the time of writing these words?:

> 
> The Lord give mercy unto the house of Onesiphorus; for he oft
>  refreshed me, and was not ashamed of my chain: But, when he was in
>  Rome, he sought me out very diligently, and found me. The Lord grant
>  unto him that he may find mercy of the Lord in that day: and in how
>  many things he ministered unto me at Ephesus, thou knowest very well.
> 
> 
>

Answer: 
The text provided in the question is an accurate translation of the [Greek text seen here](http://www.scripture4all.org/OnlineInterlinear/NTpdf/2ti1.pdf). This does not state that Onesiphorus is already dead, but gives us clues that lead to that conclusion. First, the mention of Onesiphorus' grieving family ("The Lord give mercy unto the house of Onesiphorus"), then the hope that the Lord will grant mercy in that (Judgement) day. [2 Timothy 4:19](http://www.vatican.va/archive/ENG0839/__P119.HTM) says: "Greet Prisca and Aquila 9 and the family of Onesiphorus," once again implying that Onesiphorus is dead, or at least absent. 

We can pause from looking at the actual words of the passage, to look at the context in which Second Timothy was written. Although traditionally attributed to Saint Paul, [most modern critical scholars argue that 2 Timothy was written after Paul's death](http://en.wikipedia.org/wiki/Second_Epistle_to_Timothy#Authorship). Paul never mentioned Onesiphorus in his undisputed epistles, so it is likely that Onesiphorus was a literary construct invented by the actual author of *2 Timothy*. 

Returning to the meaning of Greek words in this passage, the name Onesiphorus means ‘bringing advantage’. When we consider that Onesiphorus is singled out as someone not ashamed of Paul’s imprisonment and was the one person who sought out Paul in Rome, when others had abandoned him, then he truly did bring advantage. Although Greeks were sometimes given aspirational names, the appropriateness of Onesiphorus in this case is further evidence that he was a literary construct and existed only within Second Timothy. Onesiphorus was not dead if he never lived.
According to the current official teaching of the RCC, purgatory is not a place to PAY for one's venial sins, but a place of purification to prepare the deceased 'Christian' to live in heaven. Thus, purgatory implies that the person enduring it already has full pardon or mercy in Jesus. The person's sins are redeemed by Jesus' death on the cross. The person in purgatory is said to already be forgiven. The person is assured heaven in the official view and so we cannot conclude that 2 Timothy 1:16-18 is proof of purgatory. So is it then proof of hell then? We cannot conclude that either for the fact that mercy is assured to the one who has met the conditions of divine pardon in this life. If Onesimus was dead and Paul was praying for mercy, then it would imply Paul was praying that Onesimus would be able to avoid hell. And such an interpretation would also be speculation.