Are my son’s goals realistic?

You are correct that a sub 4:20 is not realistic given the circumstances. Even if he did not have an injury and continued training at a high level, going from 4:34 to 4:19 would be a significant improvement. I would just have him focus on getting healthy. He could certainly run D2 or D3. He could also go to a community college for a year, continue training hard, enter some meets unattached and then try to get on a D1 team.

Many D1 schools also have competitive club teams.

Focus on college and getting him healthy. Pick a school he wants to go to.

Thanks for confirming all. I will say he is pretty motivated and willing to work hard, but I suppose things will go how they go for him.

it's not impossible. i had a kid run 4:32 junior year and im almost certain he would have run 4:20 this spring in his senior year, coming off a 2:32 1k on a 200m flat track during indoor. And it's likely that 4:34 was not his peak time, being so early in the season.

What kind of 400/800 times has he run?

he needs to get to work as soon as he can to build mileage. he needs to do more than he did the year before, even without a season.

I don’t think he’s ran an 800 since freshman year. He doesn’t have an FAT 400 either. I do remember end of his sophomore year he ran a 58 or 59 in trainers at probably 10:30 at night with some friends. I would imagine with spikes, blocks, not being tired that’s worth a 56 or so.

So not amazing speed but that was almost a year and a half ago, I definitely can work with him to do sprint training this winter, he’s never done it before. I only seen him get out kicked in a race 2-3 times throughout all of high school

I'd say he has a 1/7 chance of reaching his goal.

I won't say our situations are exactly the same since I didn't have an injury but after my junior year my PRs were 4:34, 9:56, 15:48 and I really had no hope of going D1. I was on around 30-35 MPW that year, throughout august going into my senior year and beyond I bumped mileage not even that much (up to 45 MPW) and saw crazy results. I dropped to 4:21, 9:39, 15:25 and figured I could've run around 4:17 last year (season got cancelled before the most stacked mile field of the year). Now I am d1 freshman. I tell you all of this to say that it is completely possible, he just has to be consistent and train hard.

Does he have a chance? Yes. I've got a guy on my team right now who was 4:32 as a junior, 4:13 as a senior. I also have a guy on my team who was 4:16 as a junior, 4:14 as a senior. I personally went from 4:29 to 4:21 from junior to senior year. I would say my improvement was slightly above average. Average would be maybe 4-5 seconds. 10+ seconds is an incredible improvement, 20 is almost unheard of but possible.