Some days it feels like when April put him back together she missed some of the pieces. Some days Donnie will be lying in bed and feel the thrumming of tainted power burning through his skin. Some days Donnie thinks that if he doesn't focus on holding himself together, he'll just fall apart, fall to pieces, disintegrate into nothing and stop existing.
He doesn't tell his brothers. He doesn't tell his brothers a lot of things. Things like the chances that they will all live to reach 20 (2.0015%), that if the mutagen spill that got into the water supply diluted then it might have gotten into Mercy Hospital's water supply and killed 23 patients. That he's not actually a doctor and he doesn't have real medical equipment.
He doesn't tell his brothers things they don't need to know. They have enough to worry about as it is. This is just another burden for him to carry.
The phantoms are getting worse, though. And watching his brothers die againandagainandagain is doing nothing for his anxiety.