Conley left the show on day ten and later revealed he had stopped taking his anti-depressant medication while appearing on the programme.
Bristow, who finished the show in fourth place, told The Sun that producers failed to meet their "duty of care" towards the comic.
He explained: "The bosses should have taken him out beforehand. Where are those doctors that are supposed to be in the camp? Brian wasn't dangerous to us, but he could have been dangerous to himself."
Bristow continued: "Brian started to show warning signs two days before. He flipped on day eight. He was talking gibberish about things and would walk off muttering to himself all the time.
"He became very concerned about which conversations were shown and which weren't, and kept going on about health and safety, and camera angles. It was like he thought he was directing the show.
"On day nine he went up to the shed in the camp where you can talk to staff, and had a huge rant.
"He blamed them for messing up his medication by making him lose so much weight in the jungle, but that didn't seem possible to me.
"He told me he couldn't deal with the side-effects and was just going to come off the pills. But he talked such a lot of nonsense that it was hard to keep track of it. Everyone was talking about it, although nothing was aired on the show."
A spokesman for ITV said: "The safety and welfare of our contestants is of paramount importance.
"All are assessed by independent medical experts before contracts are signed, and again before entering the jungle. We also contact each celebrity's GP. Medical personnel are also available 24 hours a day and celebrities are monitored at all times."
Charlie Brooks and Ashley Roberts are now in line to be crowned Queen of the Jungle in tonight's (December 1) final.
> David Haye comes third on 'I'm a Celebrity... Get Me Out of Here!'
> I'm a Celebrity: Digital Spy readers back Pussycat Doll Ashley Roberts
> 'I'm a Celebrity' Hugo Taylor: 'Treatment of Charlie Brooks was sick'