Y’know, I’m just wondering why exactly five thought their dad would be able to help them stop the apocalypse. Yeah we know he was part of the majestic 12 or whatever, but that’s it and that’s not much of an indication he could help them. Or am I missing something? Is it just daddy issues? I feel like it’s just daddy issues
From what we've seen, it appears as though Five's decision for talking to Reginald in the 1960's was both logic driven and emotionally driven. Five makes his decisions by taking into account everything he knows of a situation and throwing it all together to come up with a conclusion or plan.
When making the decision to speak to Reginald, there were several factors present. These were:
1. Hazel gave Five a video that was a 'key to stopping the apocalypse'. Reginald Hargreeves is present in the video. Therefore, Reginald has something to do with the apocalypse.
2. Five needs to find a way to get his siblings out of the timeline before the apocalypse occurs. He isn't planning on stopping the apocalypse, just avoiding it. This means he needs to figure out a way to time travel, and fast.
3. Reginald knows more than Five about time travel. When Five ran out from dinner all those years ago, Reginald had warned him that time travelling could be catastrophic. Five didn't listen and ran out anyways. Reginald turned out to be correct.
From these three pieces of information, seeking out Reginald is a logically sound decision.
1. Reginald has something to do with the apocalypse. So if Five finds him, he may learn more information about it, and may even have enough information to prevent it and buy himself more time to get his siblings out of the 60s.
2. Five's main goal is to get his siblings out of the 60s. He can't use his powers because they are unreliable. His powers must be not working properly because they rely on math and Five doesn't have the right equation/knowledge to safely time travel.
In the 60s, Five doesn't have the time to correct his equations. It took him decades in the apocalypse to figure out how to simply travel back in time, and even then he still made an error. He can't stand to make another.
3. Since Reginald knew about how time travel worked when Five was younger, it isn't too far to hope that speaking to Reginald will reveal a hint or clue, or even a solid answer, that will allow Five to fix his equations so that he can travel his siblings back home without any more mishaps or negative consequences.
So that is Five's plan when he goes to speak with Reginald: Maybe, just maybe, Reginald has the exact thing Five needs to get his siblings safely home. If Reginald has the right knowledge, the right equations, then Five can transport his siblings back home using his powers. Just like that. It's a quick, easy, simple solution, and hinges entirely on Reginald having the right kind of information.
(Which Reginald doesn't.)
Ultimately, the meeting is mostly just information gathering. Five doesn’t have very many options available to him, but Reginald has the potential of knowing about both the apocalypse and how to time travel. So speaking with Reginald has the potential to give Five an informational edge to come up with a new plan.
(Five does get an informational edge, the seconds-not-decades advice, but it isn’t immediately useful. So Five is sent back to the drawing board.)
That said, there's a bit more to Five talking with Reginald than just Reginald having the key to Five finally getting the right equation to get his siblings home.
It's a bit smaller, a little bit less important to the grand scheme of things, but Five has a lot wrapped up over seeking out his father for advice. Five doesn't have Daddy issues with Reginald, so much as he has a boatload of guilt and regret.
Five is still someone who is very much stuck in the past and hasn't moved on. He has a lot of trauma wrapped up in time travel. The day he ran out and time travelled for the first time still haunts him. His entire mission to keep his siblings alive stems from seeing them dead in the apocalypse. Five, in a lot of ways, is still stuck over what happened to him.
The way Five sees it, Reginald is an authority figure on time travel because he was right. When Five was thirteen, Reginald told Five that he shouldn't time travel.
Five did it anyway and suffered the consequences.
Not only was Reginald right about time travel and Five didn't listen, but Reginald was right and it kicked Five in the ass for decades. Because of that one choice to not listen to Reginald, Five was firmly stuck in a world of ash, death, and isolation for half of a lifetime.
From his experiences, Five has learned that he should have listened to Reginald the first time around. And when a situation presents itself for Five to go to Reginald for advice? Well. Reginald is the most viable authority figure Five knows. He was right about time travel once before. He’s likely to be right again, if he knows something that can help.
So Five seeks him out. Because Five can’t fix his equations on his own. Because every single time Five has time travelled with his own calculations, he has done it wrong in some way or another. Because Reginald knows about time travel, warned Five about it, and was correct. Because last time Reginald gave a piece of advice that Five didn't heed, Five ended up in the apocalypse. And because Reginald was the only one to ever really warn Five of the consequences of time travel and know exactly what they were talking about.
Five recognizes that he needs some kind of help, and most promising opportunity that presents itself lies with his father.
So Five chooses to talk with Reginald. Because Five doesn’t have many other good options. Because maybe, just maybe, Reginald will know what to do. And because maybe, just maybe, Reginald will be able to give him advice, like he did all those years ago when Five was actually thirteen, and foolish and refused to heed it.
And because maybe, just maybe, Five can use that advice to save his siblings and finally return home. Because this time, when Reginald gives his advice, Five plans to actually listen.