Erstwhile means 'former' or of 'times past' or 'one time', 'previous' or 'late'. Your question suggest that the son has been disinherited or gone away and not been seen for some time or may even have died
Erstwhile Records was created in 1999.
Erstwhile means former, previous, or in the past.
the man was very erstwhile when he walked
Erstwhile Susan was created on 1919-11-16.
After the deaths of his erstwhile cellmates, the surviving prisoner was finally released. I found that my erstwhile partner had been embezzling from our business.
The word "erstwhile" is an adjective. An example of a sentence using the word would be: The erstwhile hero of the town was now a bitter old man.
erstwhile
Mesopotamia
"He had to get up a half-hour early to do the chores in the barn, but since his erstwhile ranch hand had left for greener pastures, there was no one else."
himesh
Till then or now; heretofore; formerly.
Fatayi Bayewumi-his erstwhile band manager.