So, first of all:
How would this even work? if we did this that would basically make eggy inkmatas and collector's adopted son, which would get weird pretty quick, especially since inkmatas is already shipped. And one of the main things about the collector is that he's alone, almost completely separate from the rest of the characters.
Second:
Since he ages 10x slower than a normal person, that would mean for him to be an adult in the present (assuming he was twelve when his planet exploded) they'd have to take care of him for 100 years, which since inkmatas didn't unlock her immortality until recently that would really not make sense, unless she started helping late in the process.
Third:
My thoughts, I think we should just leave it as it is. Maybe put the collector into his backstory a little bit if eggy really wants to add him in. And since he's been aging for hundreds of years inkmatas wouldn't have been alive at the time, so there's no real way of putting her in.
Caption this Meme