TJ Jackson cannot continue to serve as a surrogate parent to Michael Jackson's 3 kids without getting some compensation, so the Executors of MJ's Estate are asking the judge to give TJ a reasonable amount of money to keep the ship afloat. The Executors filed legal docs -- obtained by TMZ -- in which they say TJ has been extremely devoted to Paris, Prince and Blanket since MJ's death. TJ -- who is now a co-guardian along with Katherine Jackson -- spends 40 hours a week caring for the 3 kids. The Executors say it's been a hardship for TJ -- who is married with 3 kids of his own. Although he's been a co-guardian since July, he hasn't received a single penny for his services. The Executors are asking the judge to allow them to pay TJ…