As Dustin's possessions were completely gone leaving a boy who was literally losing everything barked out "Mark!" and that was his decision. The extremely small 16 year old started growing large as he was aging. limbs stretching, body hair popping out in new places, a bigger dick size, and everything growing to what you'd expect from a man in his early thirties. The room seemed to morph into a master bedroom and Dustin was able to look in a large mirror and what reflected back was his father's face. Although about a decade and a half younger at least...
If the universe was a teen or overworked employee it would be groaning. Someone had messed something up by removing something so it cleaned up the mess... Now that same someone messed things up again by re-add those things that were originally removed. Sure there were a bunch of details that were different, but now the universe had to reapply a lot of the continuity. Thankfully for Ty the universe didn't have any personality or agency, and even if it did "Ty" no longer existed. For that matter "Dustin" didn't exist either, although it was possible that some time in the future some version of him may pop up again.
Continuity re-established the new Mark had a nice shirt and some slacks retroactively added onto him as if he were preparing for a nice dinner somewhere. Then there was a knock on the bedroom door so he asked "Who is it?" and was confused a bit not used to the voice the man had technically been using his whole life.
"Oh Dear you know who it is." came a soft feminine voice from the other side.
"Mom?" Mark asked recognizing her general sound, but could it be that June had gotten younger as well? or... What was going on? Mark no longer felt like he was being erased, but reality felt off. Now that he was thinking he had all of Mark's memories and experiences. The boy in his father's position had the memories of two childhoods, but his childhood as Dustin was a little less vivid. He knew he had been Dustin, but also that Dustin had never existed. He also remembered meeting with June, going on dates, getting married, and now they were going out for dinner.
"Maybe leave the roleplay for after dinner while we're in bed." said June on the other side of the door. The woman opened the door to the master bedroom, and she was beautiful. No wrinkles on her face or sagging breasts. Smooth skin, and supple breasts really made who had once been his mother look really pretty. "Is something wrong? Did something get stuck in my cleavage or are you just being pervy?" June asked her husband.
Mark blushed a little and said "Just admiring my wife. Let's go to that dinner then." as he started to get up so the two could go on their date.
In the car June was smiling happy with the way everything had turned out. She had even been able to keep her powers in the transition from Ty. For years she was concerned her breasts were a little small so she was now finally able to add a cup size or two to really fill out her figure. While Ty had detested both June and Mark and had been planning on him and Dustin doing this whole thing for just a short time... Being June had granted him her memories. Being a young girl, going through puberty as her boobs grew, getting her first period, experimenting... finding Mark... This existence gave Ty a different look on June, and June really did love Mark. It also helped that it was actually Dustin piloting Mark and the Ty within June would have fun using their powers to mess with their significant other. However who now knew how long he'd be fine doing this? One way or another Mark and June were going to have fun.