Your father had more than one delusion near the end.

But on the night before he died he told me this elder son of his was dead.

This was written before that." "Tell me exactly what he said." The tutor repeated as nearly as he could the conversation of that memorable night.
"Is it not more probable that a fortnight earlier his mind might be clearer than at the very moment of his death ?" "It is possible, of course; but the letter does not seem to show it.
Besides, the inscription at the back of the portrait (which you have forgotten) is a distinct record of the boy's death.

I wish you had not shown me the letter, because the only advice I have to give you is that you do with it what he invites you to do." "Look here, Armstrong!" said Roger, getting up and walking restlessly up and down the room; "you mean kindly, I know--you always do--but you don't seem to realise that you are tempting me to be a cad and a coward!" The tutor looked up, and his eyebrow twitched uncomfortably.

Roger had never spoken like this before, and the heat of the words took even him aback.
"You asked my advice, unfortunately, and I gave it," said he, rather drily.
"Do you think I should have an hour's peace if I didn't do everything in my power to find my brother now ?" retorted the boy.