S.T.
this is a false equivalency for starters. there's a HUGE spectrum of 'normal' friendships, and a vanishing small number of 'pathologic' ones among 7 year olds.
i think your son and leo have a pretty normal friendship, despite leo's clinginess. some kids are needier than others.
i see much more of the 'pathologic' in your micromanaging of the friendship. sleepless nights? really?
i ALWAYS cried when sleepovers with my bestie ended. i remember my mother exasperatedly promising we wouldn't have any more sleepovers if it kept happening, but she actually got it- at that age it was just hard for the fun to end. a few tears among 7 years olds does not equal pathological.
i absolutely agree with you encouraging your son to widen his friendship circle, and not to get too intensely one on one with young leo. but it sounds like what you really want is for him to cut ties altogether. that goes against your stated purpose for your son to demonstrate kindness, and to play with everyone.
it's also not unusual for kids to go through phases of intense closeness with another kid, where they just want to play with each other.
i find it a little ironic that you refer to leo's parents as 'the ultimate helicopter parents' when you're losing sleep and requesting class placements in order to manage your own child's schoolyard friendships.
khairete
S.