This issue would not have come up if a missing player policy is in place beforehand.
Our group policy is this:
If you don't want anyone to play your character, then your character is on business elsewhere for that session. You get no XPs or any other perks as your character was not present.
If you want someone to play your character, designate another player to play the character. Your character shares fully in the rewards (XPs, treaure, etc).....and shares fully when life and circumstance is not kind to the character or party (Meaning, your character can die).
I have found that most players IMC over the years, don't mind someone else running their character. I had a few players who didn't want anyone to play their character, which is fine. In those cases, if the character was significant, I had a NPC stand-in so the rest of the party didn't suffer due to the absence of that character.
And if the 'no one plays my character' players complained when their character was 1 or 2 levels behind everyone else (due to missed XP), I remind them about the choice they made.
It was worked fine this way IMC for many years.