Try to make this a quick response…
Not fully knowing his training background and seeing him in person, it really is hard to make snap judgements but I am going to. If he was my athlete, I would focus more on getting him fit and making smaller goals for this first season back after illness. Putting in the kind of work that it would take to run that kind of time would mean taking too many risks. For someone coming back from a serious layoff, my priority would be to keep them progressing and happy with the now.
I don’t recall the 08’ fields but would imagine that it would take 3:40 - 3:41, at the slowest, to actually get on the track in Eugene, ,meaning around a 3:58 1609 meter (mile) time.
Based off your limited info about the athlete, he appears to be more of an 800/miler, showing more foot speed, than a miler/3k runner. I would train him with that in mind, focusing more on his strengths, while not neglecting his weaknesses. Putting that on paper, a 2 week training schedule would have 4 quality workouts (1 800 focused, 2 that are mile paced focused, and 1 workout that was v02max/LT type). This would typically involve a race at least 1 time every 2 weeks but ideally each weekend.
Your athlete doesn’t have the foundation of stress built up to safely attack a plan like the above, without having to modify the workload of each workout, as well as the paces.
I would work on getting his volume and consistency of training up to 6 days a week, hoping to get at least 30 miles a week. That type of jump wouldn’t have to take more than a month. For workouts, I wouldn’t do anything other for the first month (aside from a moderate mileage jump) than getting on the track, 1 x a week for 4 - 6 x 200 or 300 at a goal 3k pace. It is quick enough to start knocking the rust off without stressing the body too much and setting him back too far recovery wise. Those types of workouts will be a good foundation for moving forward to real track work, bridging the gap from no quality track work, to getting his feet a bit wet.
There are a hundred ways to skin a cat. My advise as someone who has ran at the level your athlete is looking to get to and someone who has coached NCAA qualifying mid-distance runners, is to take is easy and keep it fun. Congrats on reaching out for more information for your athlete. Many coaches are too stubborn or prideful to take that first step.