Suppose I have dataframe like this:
HTML Code:
  family relationship meanings              edu  
1      1 A            respondent                   12  
2      1 B            respondent's spouse     18  
3      1 C            A's father                      10  
4      1 D            A's mother                    9  
5      1 E1           A's first son                 15  
6      1 F1           E1's spouse                 14  
7      1 G11          E1's first son               3  
8      1 G12          E1's second son          1  
9      1 E2           A's second son             13
10      2 A            respondent                  21
11      2 B            respondent's spouse    6
12      2 C            A's father                    12
13      2 D            A's mother                 16
14      2 E1           A's first son               18
15      2 F1           E1's spouse               15
16      2 E2           A's second son           17
17      2 E3           A's third son               16
relationship: relationship in one family.

meanings: the meanings of second column "relationship".

I want to calculate the father generation’ maximum education year in one family. We do not need spouse's information. The expected results are as follows:

HTML Code:
 family id      edu fedu  
1      1 A        12 10    
2      1 C        10 NA    
3      1 E1       15 18    
4      1 E2       13 18    
5      1 G11       3 15    
6      1 G12       1 15    
7      2 A        21 16    
8      2 C        12 NA    
9      2 E1       18 21    
10      2 E2       17 21    
11      2 E3       16 21
Thanks!