Re: Dhrishtadyumna being educated by Drona.
Was the old rishi crazy to educate the same boy adopted to kill him?
Nothing suggests Drona was that suicidal.
I believe Dhrishtadyumna was actually a student of Drona, adopted by Drupada later.many Yadavas did send their sons to Drona. As the student, Dhrishtadyumna would've known Drona's tricks enough to defend Panchal against him.
https://www.hinduwebsite.com/sacredscripts/hinduism/dharma/manusmriti_1.asp
36. In the eighth year after conception, one should perform the initiation (upanayana) of a Brahmana, in the eleventh after conception (that) of a Kshatriya, but in the twelfth that of a Vaisya.
37. (The initiation) of a Brahmana who desires proficiency in sacred learning should take place in the fifth (year after conception), (that) of a Kshatriya who wishes to become powerful in the sixth, (and that) of a Vaisya who longs for (success in his) business in the eighth.
38. The (time for the) Savitri (initiation) of a Brahmana does not pass until the completion of the sixteenth year (after conception), of a Kshatriya until the completion of the twenty-second, and of a Vaisya until the completion of the twenty-fourth.
39. After those (periods men of) these three (castes) who have not received the sacrament at the proper time, become Vratyas (outcasts), excluded from the Savitri (initiation) and despised by the Aryans.
Ie, a child thought to be suitable for brahman varna is ready for upnayan at age 8, a kshattriy, at 11, and a vaishya, at 12. If the parents wish, the child may begin earlier at ages 5, 6, and 8, or latest by ages, 16, 22, and 24 respectively. There is no Upnayan after these ages and one will be in shudra varna.
Manusmriti also says education is 12, 36, or 48 years
Dhrishtadyumna being an Angirasa would be brahmana. If he started at 8 and finished in 12 years, he would've been 20. Maybe a year or two passed before adoption. Maybe he was YOUNGER than Panchali, not older or twin. But they came out of the fire together. That's it.