Since Dogface has already explained that I can’t answer his question, it may be pointless to try.
Nevertheless:
My interpretation of the proposed law in Germany is that it is based on a belief that families inherantly should have rights and influence over and above that of single individuals, and therefore more votes than is possible under a “one man, one vote”, scheme. In much the same way, there used to be a common assumption that property owners inherently had more rights than other citizens, and so should be permitted more than one vote each. What I am saying here is a restatement of what I said, in straightforward fashion, in my first post.
The practice of allocating additional votes to property holders was still observed in Northern Ireland as late as the 1960s. Possibly it is still in force elsewhere. (“Elsewhere” means “in another place”, as, for instance. Germany is “elsewhere” than The United States).
It is interesting that the proposal seems to assume that families will vote in a bloc. If a mother votes for one party, and a father for another, and they have one child, how then should the child’s vote be counted?
I am reminded that when Jimmy Carter was in his first term in the Georgia legislature there was a bill proposed granting voting privileges to the dead. It was reasoned that the families of deceased persons would know how they would have intended to vote, and there was an extended debate as to how long families should be entitled to vote for relatives who were deceased.
As for the idea that the party proposing the idea may have hopes of ingratiating themselves with families, I expect this is the case. Political parties nevertheless generally argue a reason or a rationale behind a law beyond the fact that it is to their political advantage.
With regard to the change of the minimum voting age in The United States, IIRC, much of the debate at the time centered on the fact that 18-year-olds were, at the time, being drafted to serve in Vietnam.