Can someone come back to life?

Yes they can. Clinically dead people can be brought back to life with the right equipment, that which can restart the heart and lungs. The only way for a biologically dead person (where cells in critical organs die off...) to come back to life is by Jehovah God resurrecting them. This He will do in the future. (John 5:28-29; Acts 24:15) We can count on this to happen because not only is Jehovah the source of life itself (Psalm 36:9), but He can't lie either. (Titus 1:2)

There have also been numerous examples of resurrections that have already occurred in the past. The prophets Elijah (1 Kings 17:17-24) and Elisha (2 Kings 4:32-37), the apostles Paul (Acts 20:7-12) and Peter (Acts 9:39-42), and even Christ had performed them. (John 11:11-44)

(New World Translation of the Holy Scriptures)