George seems unlikely as a child as he is not in the The Book of Carlaverock and the connection to this specific John is unsourced.
Sources
↑Paul, James Balfour. The Scots Peerage : founded on Wood's ed. of Sir Robert Douglas's Peerage of Scotland; containing an historical and genealogical account of the nobility of that kingdom, Edinburgh: David Douglas, 1909, Vol. VI, Archive.org,
p. 477
↑Cokayne, George Edward, The Complete Peerage of England, Scotland, Ireland, Great Britain and the United Kingdom, London: William Pollard & Co, 1932, Ed. 2 Vol VIII, FamilySearch,
p. 591
Hi Enrique and Theresa, John's parents didn't marry until about 1454, and his mother was born about 1436. So I'm amending his date of birth. I'll add some sources to support. Hope that's ok. Gillian
I've rejected the match between this profile and the profile of Robert Maxwell , who is his son. They are both married to women named Agnes Stewart, but these are totally different women.
George Maxwell-1067 born about 1510 seems to be the only child born within John's life (he was with profile showing John b/d 1436-1513; rest of children were with profile showing John dead at 5 years old in 1459).
I'm going to go with the dates in Maxwell-1567 instead of Maxwell-658 (Maxwell-658 has born about 1454 in Carlaverock, Dumfries, Scotland, UK & died 1459 in Scotland, UK, yet married and had a bunch of kids in those 5 years).
alongside the more detailed bio from The Book of Carlaverock already linked
http://www.our-royal-titled-noble-and-commoner-ancestors.com/p1365.htm#i41013
More research must be done before these two profiles are merged.