He notes where the apartment is relative to the rest of the building. He goes outside to see if he can spot them through an window.

Nope.

Okay, any problem if he just leaves the red district?

No one stops him.

Okay, Felix goes back to his home dimension and collapses on the ground.

He spends a very unproductive while in misery, loneliness and feeling like a horrible person who kidnaps people and can't even be competent about it.

Eventually he falls asleep.

Weird dimensional activity since last time he was asleep?

The other pocket dimension grew some.

His house has a server set up to receive info dumps from radio signals. Felix sends "snapshots" of the child and father location at regular intervals, starting since he left them. This is tricky - because of format conversion - it would be easier to create scale models but those occupy space and aren't searchable. He multitasks by sending infodumps with other useful information. Like news about reds in the last week, every bit of communication that the people he met had since Felix arrived in this world, minus the intercaste family and Afen.

Father and child appear to have gone to another apartment, and then father to work. 

Reds don't make the news much. The credit allocations for the spring were announced, including 68,000 red credits.

The blues have been faithfully sending their department reports on Felix. Their assessment is that his world has powerful magic that'd be of tremendous use, possibly ending population pressure, but that he's opposed to sharing it for practical reasons (the extent of practical concerns are hard to assess at this time) and because of personal trauma related to misuse. For the latter reason he's also declined to explain what precautions they should take about extant dreamshapers (there are two. One is red. The red is apparently in Felix's custody, and whether this is an adequate precaution they're not clear on. They're trying to identify the red.)

...Felix debates for a bit and then creates a portal in the hallway outside the apartment and then a portal inside the apartment.

He doesn't know how to interpret the lack of news nor the quantity of credits.

The reports aren't unfair, he supposes. He really needs to pull himself together.

He goes through the hallway portal. And knocks.

No answer.

Felix walks back through the hallway portal and then through the portal inside the apartment.

A very elderly woman blinks at him and then slowly stands up from the couch where she's sitting.

Felix watches her.

"You're in my house," she says.

"I know. No one answered the door."

"I will open it now and show you out."

"Lafa's kid."

"Young man, you will drag my great-great-grandson out of my house over my dead body."

"Have they told you...?"

"I am sure you have a reason. I am sure it's an important enough reason to kill me over, idle whim is enough reason to kill a red. But I'm telling you that you will have to."

"He has magic. That thing I just did. He could do it too."

"Get out of my house."

"Okay," he walks through the portal.

...she goes to find her great-great-grandson. He's crying in a closet. She holds him.

Felix is mercifully unaware of this exchange.

He goes to Lafa.