(SPOILER DETAILS FOLLOW)

Something I don't understand is how is it that Minna's son and Dick readily know and seem sufficiently fond of one another, the boy seeing and happily greeting "Uncle Dick", yet the boy's own father, Tom (Dick's older brother), doesn't even seem to realize Minna's child by him (Tom) had survived? She tells him, in the confrontation scene in England, that their baby died a few days after it was born. Have Dick and Tom been so completely out of touch for over a decade to the extent that it never came up in normal conversation or correspondence between the two that Minna has had a living son all those years, and that the boy and Dick know one another, and that the boy recognizes Dick as his uncle?