S., I'm a mom of two sons that we chose to have just less than 2 years apart. They are now 25 and alomst 27 and have matured into fine young men that make me quite proud. When they were younger, they too made mistakes because they were in a hurry and not thinking. Much of what you are seeing is probably due to boyish immaturity. It sounds like your son is very caring and wants to be less "accident" prone. If you choose to "punish" him, the punishment should be natural consequences. If somethng gets broken and it needs to be repaced or fixed, have him either help fix it or have him contribute financially towards the repair - even if that means he has to do some extra jobs around the house to earn a bit extra so that he can help out with the repair. (Not that he can earn enough to actually pay for the whole repair/replacement, but only a portion of the whole cost, perhaps a small portion if it is expensive.) If he breaks a favorite toy, the natural consequence is that he no longer has the toy to play with or he would need to buy it for himself to replace it either with birthday money or allowance. That, in one sense makes him feel better about himself because he can be part of the solution to the problem he caused. I don't mean that this should happen every time, but sometimes perhaps. One time my older son was washing dishes by hand for me and somehow managed to break two very expensive crystal glasses. To this day I don't know how it happened and he was very sorry. I was very disappointed that they were broken, but there was no way he would have been able to pay for them and they were so expensive that I chose not to replace them. It happened by accident. I had to let it go. However, when he was about 12 we were on a camping trip with our youth group and he was with many of his friends. We were getting ready to leave and he had gone to tell one of his friends from another group good-bye. When he came to the car on full run, he decided to just jump through the open window of the Suburban to his back seat. Unfortunately, the glass was not all the way down and when he jumped through the window, he put his foot somehow on window and it broke. My son did not have ADHD or other issues, he just was excited, in a hurry, and not thinking. In that case, he had to sit by the open/broken window on the way home and then he had to help pay for the window. That was the only punishment he received; he understood. Thankfully our insurance covered much of the glass cost. He understood and it helped him slow down and think in the future even though I doubt that he paid the entire cost that was left after the ins. We weren't ugly or angry about it, but he knew that he should have been more responsible, and we did not keep bringing it up to him either how he had messed up.
Both boys had accidents where things got damaged/broken or they got hurt. Stuff like that is going to happen, and I don't mean to sound sexist, but I think that it happens more with boys than with girls. I grew up in a family of all girls and I don't remember it happening much. But I raised a family of all booys and, trust me, the "accidents" happened. Much of what you see with Tobias' accidents I'm sure will disappear when he gets a bit more maturity or, like it was with my sons, they are just different types of accidents based on what they are into.
I loved raising my boys. To give you a bit of hope, my sons have lots fewer accidents now than they had when they were boys. They are rare now. Hang in there! Make sure Tobias knows that you love him no matter what "accident" happens and that he is more important than stuff. Stuff can be repaced or lived without, Tobias can't be replaced or lived without. God bless you as you raise your precious children. (Sorry that this became so lengthy.)
Carol B