from my humble opinion it depends on the intention of the father (who is buying) and the character of the one receiving. I think anything above RM2k is a little too much (my personal opinion).
However, i take note that watches are character building tool as well. It can build up one maturity and tendency to value this time telling tool and the art of it being produced. Being a father, i started to sense my son's started to develop interest in watches and both my son and daughter now started to develop good habit of arranging their watches at a dedicated place when its not in use. In short, they started to value their watches although the watches are inexpensive.
So, to decide whether should it be a Rolex, or a Tag or a AP RO or an Apple watch or anything under the sky, probably the two mentioned characteristic is to be considered should money is not the issue. In my cases, i don't mind receiving anything from my ada and would try my best to just treasure it even it is just a fake Rolex.