Howdy,
having a piece of driftwood in my tank which I collected myself is just one of the beautiful aspects of our hobby. It'll always remind me of the great place and day I harvested it, canoeing with friends.
Self-harvested driftwood is not a danger - if you know what to look for! It has to be well aged under water, washed out bu nature and it must have been dead for years. To judge all that is quite easy once you actually look at some of the driftwood in rivers a little more closely. Any bark on the wood and it's too young. The wood should not come out of the mud but out of flowing water. That's basically all.
At home, a high-pressure cleaner works best to get rid of dirt. Then, you can either boil it or soak it in brine for disinfection. Thus, I do not share the worries stated above about marine driftood. I soaked my piece for three days in a bathtub with brine. Then simply soak it for another few days in daily fresh water. And you have a perfectly safe piece of driftwood. Note: I do not go canoeing in rivers with industrial outflows!
Seriously, if your buddy found the right piece, it's perfectly safe. Especially after drying for a year, no disinfection will be needed any more.
Guys, go back to the roots of our hobby. Our forefathers didn't buy decoration material but put in their tanks what they found. Just because you pay for some wood doesn't make it safe...
HarleyK