Exceptional trainer is very good, and this exceptional has a "dream" current salary. You could have him on your team for at least 4 seasons. After that his salary will be around 60k/week (I think). At that point consider your economy. His annual salary will be around 900k. If you think it's still manageable keep him that season but also keep some money for your next trainer.
Also, very important. Trainer is good when he is on duty :) So be sure to secure maximum trainees for this season. If you're short in trainees, and have some money left, check the TL. You can find some decent 18y, allstar-perennial allstar potential for around 200-400k everytime you check the TL.
Also target which player on your roster will you sell next season. Train him alongside
(13195286) (who you said is your main training target). He will improve. Next season he'll worth higher in the TL.