Difficulties with subsetting clustered family data - subset

Question

I am trying to subset the following dataset so that both sons and fathers with resting heart rate values are included in a new data frame. When I use the is.na function, since fathers and sons are on their own individual rows, fathers without a value for sons' resting heart rate are deleted and vice versa.
I have tried the following code but I am not having any luck:
for (i in 1:nrow(datadiss)){
if (datadiss$Fatheridorsonid == "sonid" & isFALSE(is.na(datadiss$sonrhr))){
data2<-datadiss[which(datadiss$sonrhr>0),]
}else if (datadiss$Fatheridorsonid == "Fatherid" & isFALSE(is.na(datadiss$dadrhr))){
data2<-datadiss[which(datadiss$dadrhr>0),]
}
}
An example of my dataset can be found here:
structure(list(fid = c(1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 5, 6, 6,
6, 7, 7, 8, 8, 9, 9), sonid = c(15576123, NA, 3100866, NA, NA,
13206733, NA, 3098080, 3938697, 7089160, NA, 10580951, 13465844,
NA, 10801693, NA, 10797768, NA, NA, 9670190), sonrhr = c(75,
NA, 89, NA, NA, 100, NA, 65, 62, 56, NA, 78, 85, NA, 67, NA,
66, NA, NA, 87), sonbmi = c(19.66, NA, 19.59, NA, NA, 21.54,
NA, 22.84, 22.88, 29.09, NA, 21.53, 22.03, NA, 23.41, NA, 22.02,
NA, NA, 22.44), sonphysenerg = c(329, NA, 234, NA, NA, NA, NA,
295, 344, 299, NA, 313, 351, NA, NA, NA, NA, NA, NA, NA), violent = c(0,
NA, 0, NA, NA, 0, NA, 0, 0, 1, NA, 1, 0, NA, 0, NA, 0, NA, NA,
0), nonviolent = c(NA_real_, NA_real_, NA_real_, NA_real_, NA_real_,
NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_,
NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_,
NA_real_), Fatherid = c(NA, 15576243, NA, 3100889, 123456, NA,
3938697, NA, NA, NA, 10580442, NA, NA, 10804692, NA, 10797798,
NA, 12797798, 9670176, NA), dadrhr = c(NA, 76, NA, 87, 49, NA,
67, NA, NA, NA, 57, NA, NA, 78, NA, 58, NA, 100, 89, NA), sonorfather = structure(c(1L,
2L, 1L, 2L, 2L, 1L, 2L, 1L, 1L, 1L, 2L, 1L, 1L, 2L, 1L, 2L, 1L,
2L, 2L, 1L), .Label = c("Son", "Father"), class = "factor")), class = "data.frame", row.names = c(NA,
-20L), codepage = 65001L)