Prince William will reportedly keep a close eye on his estranged brother, Prince Harry, after the latter unexpectedly moved back to the UK. “William will be watching his brother very closely and trying to work out what his game plan is,” Grant Harrold, a former royal butler, told Us Weekly in an interview published Wednesday. Harrold believes William is still upset over Harry’s bombshell allegations about their relationship exposed in the latter’s 2023 memoir, “Spare.” “I don’t believe he’s happy Harry is back in the UK at all.” A source told the outlet that the brothers’ “relationship was already broken,” explaining, “The move doesn’t…