My lovely FIL is gravely ill having been diagnosed with a very aggressive brain cancer. His decline has been very rapid - just last week he was at our house for dinner, and speech was impacted to a degree and motor function in his hand was starting to go, but he was himself and able to walk and communicate.
We had waited until GCSEs were over until we told the DC that it was in fact a brain tumour - initially medics thought it had been a TIA, so DC have only been aware that it is serious and terminal since Thursday, and at that stage we thought he may have another 3-4 weeks. DS (16) went to a week long camp on Saturday - at least 12 hours travel and a ferry away and he isn't due back until Friday night. I don't think FIL is going to last more than a couple of days at most - he is no longer able to eat or drink.
I can't bear telling DS when he is away and not being there to support him, yet I think DS would be devastated to only learn when he gets back and that we had kept it from him. Both DC adore their grandparents. What do I do?