I call bullshit on your having a character that can, apparently, manipulate physics on a highly specific level without running afoul of the standard model or other quantum mechanical effects. You said that they can only lift a certain amount; they weigh more than they can lift and thus cannot fly.

Telekinesis should at [i]no[/i] point cross over into a theoretical scenario involving negative mass. It definitely shouldn't lead to [i]creating[/i] negative mass.

Also, by the way? Doing that would just explode the character.