WELS’ confession regarding salvation

My grandma is a WELS Lutheran, but my grandpa was Catholic. Everyone in my family was raised and are practicing Catholics. My grandma's WELS pastor told her (in front of my aunts and uncles- at her sister's funeral) that he felt bad that her children and grandchildren are not saved and that we are all doomed to hell. Is this really what the WELS religion believes?

I was not privy to the conversation you referenced, but I can tell you what we in our church body believe about salvation.

“We believe that God has justified all sinners, that is, he has declared them righteous for the sake of Christ. This is the central message of Scripture upon which the very existence of the church depends. It is a message relevant to people of all times and places, of all races and social levels, for ‘the result of one trespass was condemnation for all men’ (Romans 5:18). All need forgiveness of sins before God, and Scripture proclaims that all have been justified, for ‘the result of one act of righteousness was justification that brings life for all men’ (Romans 5:18).

“We believe that individuals receive this free gift of forgiveness not on the basis of their own works, but only through faith (Ephesians 2:8,9). Justifying faith is trust in Christ and his redemptive work. This faith justifies not because of any power it has in itself, but only because of the salvation prepared by God in Christ, which it embraces (Romans 3:28; 4:5). On the other hand, although Jesus died for all, Scripture says that ‘whoever does not believe will be condemned’ (Mark 16:16). Unbelievers forfeit the forgiveness won for them by Christ (John 8:24).

“We believe that there is one holy Christian church, which is the temple of God (1 Corinthians 3:16) and the body of Christ (Ephesians 1:23; 4:12). The members of this one church are all those who are the ‘sons of God through faith in Christ Jesus’ (Galatians 3:26). The church, then, consists only of believers, or saints, whom God accepts as holy for the sake of Jesus’ righteousness, which has been credited to them (2 Corinthians 5:21). These saints are scattered throughout the world. All people who believe that Jesus is their Savior from sin are members of the holy Christian church, regardless of the nation, race, or church body to which they belong.

“We believe that this holy Christian church is a reality, although it is not an external, visible organization. Because ‘man looks at the outward appearance, but the Lord looks at the heart’(1 Samuel 16:7), only the Lord knows ‘those who are his’ (2 Timothy 2:19). The members of the holy Christian church are known only to God; we cannot distinguish between true believers and hypocrites. The holy Christian church is therefore invisible and cannot be identified with any one church body or with the total membership of all church bodies.”

Those statements are from This We Believe, a statement of belief of our church body. The first two paragraphs are from the section titled “Justification by grace through faith.” The last two paragraph are from the section titled “Church and ministry.” This link will take you to the complete document. I hope this information is helpful for you.