Never thought I'd say this, but Jay's staying in the house is good for Aaron. Jay's chances of winning are pretty redundant. He could stage a comeback with a vote swing, but he'd never beat Alex anyways. Jay struggled against Jem and I believe his appeal is limited to the sort of screaming fans on eviction nights
Aaron's main threat to winning is Alex. If Jay is evicted approx 90% of his votes WILL go to Alex the rest maybe to Louise who will get about 30 votes anyway (but Jays' votes will not go to Faye, Tom, Harry or Aaron). They would have gone to the Aden or Anton had they survived. So an evicted Jay doesn't really help Aaron.
Loads of Geordies/ northerner voters will have to shell out for Alex AND Jay or else split the vote between them. I suspect 5/8ths of Harry and Fay's evicted votes will go to Aaron.
Plus Faye will just make Aaron miserable if she's stayed. Moaning, constantly whining how she's not paying her any attention, mocking him, demanding that they discuss their relationship status, criticising his clothes etc. If she went on Friday Aaron would cry for about 24 hours and then have fun with Tom, Alex and Louise the next day. He'll get over it surprisingly quickly I suspect now that he's on the home straight!

If Harry went I reckon about 60% of his votes will go to Aaron, 20% to Alex, and the rest to the others.
Also Jay (and all his freezer loving ways) staying in the house makes Aaron look good. If Anton had stayed this week over Harry then Jem's demonisation of Aaron wouldn't have been so effective.