You could just export people whose data has changed but it would include all their unchanged data, too. Either he imports into a temp database or you generate reports from your temp database. Former and changed persons could be compared, best done using Individual Summary reports and software that can compare the two report files. You should experiment with the file types. For RTF, you will need to use MS Word while you can find a free text editor that will compare TXT files.
How do I export only those that have changed since the last export? That is, without having to select each individual manually. Exporting all their data is ok, since my uncle wants to double-check everything he enters into his db anyway. Or you mean I simply export another Individual Summary report and compare the two? Although it is not possible to include all people in the db in an Individual Summary report?
If I could simply select individuals by the last edit date, that would be enough for me. But that is not possible?