I cannot believe I’m saying this. I’m rightfully ashamed. However, if your dad truly refuses to bring the vehicle to a shop, and if you truly refuse to get it repaired for him, AND if the leak is in a hardline, at least put a piece of brake tubing around it and some small worm-drive clamps over it.
NOTE: this is NOT a good fix. And it is NOT recommended. And it should be tested thoroughly. But it’s better than tape.
Please, do NOT consider this a recommendation of a fix. Just an improvement over what you and he seem willing to do. I urge you, I beg you, I am on my knees, take it to a shop and get it fixed properly.