No one seems to have suspected Edward, Duke of York, of involvement in his brother's plot. This demonstrates the political progess he had made by hitching himself to the bandwagon of Henry V. It would be wrong to suggest that he now enjoyed the sort of influence he had under Richard II - when for a time he was more or less the King's right hand as well as his 'brother' - but he did enjoy an element of favour and was not under continual suspicion.
As I mentioned in an earlier post, Edward had enfeoffed the bulk of his own lands to support the building of Fotheringhay College. As he really could not expect to suck on the Despenser teat much longer he may have hoped for some big financial dividend from the French wars. Alternatively he may have foreseen his own death. He made a will (not unusual in such circumstances, admittedly). This acknowledged his sins to the last full measure, and he admitted that he was 'bound to pray' for the soul of Richard II.
It is sometimes said it was Edward who suggested the English archers should carry sharpened stakes with which to protect themselves. It's impossible to be sure of this, but it is certain that he commanded the right hand 'battle' at Agincourt - Henry V commanded the centre, with Lord Camoys (husband of Hotspur's widow) on the left. Edward was one of the few English 'men of name' to be killed in the battle. It appears he was crushed by the weight of others falling on top of him - alternatively, it may all have been too much for him, bringing on a heart attack. (By this time he is described as 'fat', quite likely for a medieval prince in his forties.)
I find it wonderfully ironic that Edward should die fighting for the House of Lancaster (after all his efforts to get rid of Bolingbroke), and in a French war at that (given that in his early years he had been so strong a support of Richard II's peace policy).
The bodies of York and the other nobles killed were boiled so that their bones could be taken home to England. Edward was of course brought to Fotheringhay, where originally he lay in the chancel, under a flat slab, probably with a brass memorial over him. In Edward VI's reign the chancel became a ruin, and Elizabeth I had Edward and her other Yorkist ancestors transplanted into the former nave. New tombs were erected, and can still be seen there, next to the altar.
If you'd like to take a look at Edward's tomb this link will take you to a selection of excellent photos of Fotheringhay Church on the Worcestershire Branch of the Richard III Society. The Tomb is among them.