I'm sorry you have this worry, though if you're only going to be away for a week, the dilemma might not arise. I know some religions require the funeral to take place very quickly, but otherwise they do often take place some time later.
My mother, who was 97 and had advanced dementia, went downhill very suddenly and died about a week before the entire family was going to be away for a big family wedding in France - we were all staying away for at least a week.
It would not have been possible anyway because of availability at the crematorium to have her funeral before we all left, so it was delayed until we were all back.
Similarly, a friend whose husband died, had two sons from a former marriage living abroad, one in Europe, one in SE Asia. She wanted them there for the funeral, but for various reasons they could not get away very soon, so again the funeral was delayed for about a fortnight.