The bible is silent on this point. There is no reason to suppose that he was taken up alive into heaven as Enoch and Elijah were. He is an Old Testament type (or Picture) of Jesus Christ, who was to come, but nothing offered in scripture to suggest a (rapturing) up to heaven alive, as Enoch and Elijah.
Tithing is to give to God one tenth of all you earn. It is not to pay the wages of any clergyman. It must be used to build up the kingdom of God. If you choose to give your tithe to a particular church then make sure just how that tithe will be used. If the clergy of the church have to work for their upkeep, then it might be safe to pay into that church. Abraham paid tythes to King Melchizedeck, but the king never took any of the money for himself but used it to help the poor and the needy.
In Catholic theology, the Eucharist is seen as a sacrifice because it is a re-presentation of the sacrifice of Jesus Christ on the cross. During the Eucharistic celebration, the bread and wine are transformed into the body and blood of Christ, and this sacrificial act is offered to God the Father in remembrance of Christ's sacrifice for the forgiveness of sins.