Also untrained, but do a bit of work on my bats myself.
I had an old stick that i used for probably 6 or 7 years. By the end, it started getting these cracks too.
By the colour of the timber, the tape around the shoulder, it looks like this stick is getting on a bit.
As for repair, wrap some fibre tape around the the spots a times, just to reinforce them a little.
Don't think it's worth re-handling as I don't think that is likely to help you on this one. Just the age of the bat i think friend.