Tier 4 Traveling Abroad?

Hi

I traveled at the beginning of December to Cairo to visit a my uncle who has been diagnosed with a brain tumor. I spent a week there then came back to the UK.

a week ago they called me to tell me that the scheduled an operation for the 9th of January. 

Were not from Cairo so we have no relatives there, and his son was going to travel to support my aunt while his father is in operation and help take care of him after the operation.

but my country has closed all airports and his son isn't  going to make it in time.

They have asked if I can go and support them as the doctors are telling him there are high chances he will not make it out of the operation room.

I have booked the flight before tier 4 rules came out, but now they say only essential travel is allowed.

This is essential for me, but would they consider it essential and let me fly out or will they stop me.

Thank you