full frame or keep T4i

I shot film for many years, and then digital when D30 first came out. Have had various Canon crop camera's after the D30 and now I have a T4i which has been my favorite Canon camera. I have a Canon 85 1.8 and a Canon 18-135 STM lens. Have been thinking that full frame would be better because I am not interested that much in dof, I mainly shoot my family and friends and events. Thought about keeping my T4i as a vacation camera but have thought about selling it also with the lens and using the money for a used 5DII for under $1500. If I kept it I would look for a 5D for under $600. I'm sure the 5D would be great but I have gotten so use to auto ISO that I think I would miss it. I know the focus of the 5D is not as good as the T4i but I don't shoot sports, no quickly moving small children so I don't think that would be a concern. I like to shoot indoors without flash and the combo of T4i and 85 1.8 works great, I'm sure 5DII would be as good but what about the original 5D. Thanks