You use the COUNTIFS function. For example, let sheet1 contains names in B1:B10, past due summary data in E1:E10, and other summary data in F1:F10, G1:G10, etc. Let sheet2 contain names A1:A100, past due data in L1:L100, and other data in other columns.
In E1 on sheet1 you would enter the formula
=COUNTIFS(sheet2!A$1:A$100,B1,sheet2!L$1:L$100,1)
and copy this formula to E2:E10. Cell E3 would then contain the information for John Doe.
Be aware that this would not count an entry in column L that contained a 2. If you wanted to count this entry also, then you change the final argument from 1 to ">"&0 or ">="&1 (quotes required). If you meant to count this entry twice, then you are summing and not counting and would use the similar SUMIFS function