More importantly that the spotlight will not be on her, she always likes the centre stage & to control the narrative. This will be a real headache for MM, the momentary loss of control over Harry when he’s back on uk soil and him spending time with her enemies, she will think that they will try to talk sense into him, every possible scenario will have gone through her mind. But she will of covered this with him before he leaves the US, with some cleverly crafted word salad doses. I would hazard a guess that his visit will be as short & brief as possible as MM couldn’t possibly cope without him for long.
Control has always been a key factor for MM, this potentially is a worse case scenario for her. She won’t be there to fill in his ear ‘her truth’ of every interaction & belittling of all conversations. I’m sure someone in the RF will call Harry out for his puppetry & distasteful behaviour after the funeral has taken place, but I do expect some awkward moments for all concerned during his visit for the funeral.