I would say, if possible, take a few days off yourself and show up when he plans to go . Spend those few days with him. He will remember that more than any old present. G.
Fishing gear is basically impossible to buy for a life long, dedicated fisherman. There are countless means and methods and target species... who knows what he already has... that said, a friend of mine bought me this and it's fun getting every month: https://mysterytacklebox.com/You can spend as much or as little as you want and every month a new mystery box shows up with tackle in it. Honestly it's more fun than anything, but it's pretty cool and I enjoy it.