Merlin has something to say...

Merlin is very old and we are very fond of him.
But he has taken to barking quietly but continually when he is in his bed, and staring at us in a sort of meaningful way when he is in the room with us.
We really don't know what to do. I have tried giving him some biscuits as a bribe, which works for a while but then he starts again.
I wonder if he is trying to tell us something? Like " Hey guys the worlds about to end and shouldn't we do something about it?"
Hopefully not!