I agree with the not sharing. If you tell them that it was put towards funeral costs and show receipts they have nothing to argue with you about or if it gets ugly, nothing to go against in the courts.

If there was a total of 19K taken out of your RRSPs for the funeral divided by three people is $6,300 each sibling. $4,000 divided by 3 is $1,350 each. So bottom line, keep the $4,000 and tell each sibling they owe you $5,000 each.