Yes giving your child to much will leave them being spoiled. The way to not spoil them is by not giving them to much stuff. Save the stuff before you give it to them. That way it will be a surprise and the child will be more happy of what you give them. They may also take much better care of what you give them.
Maybe
Who are you and who are you to the 20yo and his parents? Impossible to answer without knowing but I would assume the court would find that the parents have had more influence over their child than you.
You file for child support and he sue for alienation of affection.
When a child displays excessive affection towards others, it may indicate a need for attention, validation, or emotional support. It could also be a way for the child to seek comfort or security in their relationships.
relationships between child and parent, fears of unknown, innocence of child, parents' affection towards a child and its effects
motto ai o irimasu = i need more affection
There are parts of the brain that do not develop properly this is particularly the cas with boys.
Try to being more affectionate yourself first.
The spoils system.
The three main types of spoils are cultural spoils, environmental spoils, and economic spoils. Cultural spoils refer to the destruction or damage of heritage sites and monuments, environmental spoils involve harm to natural resources or ecosystems, and economic spoils involve the appropriation of wealth or resources by an invading force.
Spoils system
Probably not. But if that parent was ordered to pay child support and is not doing so, then they can be sued for that.