Second language - Spanish or German?

DH is German and occasionally does business in Germany and he says that generally English is used and to be honest when we go there it’s very very unusual to find people who don’t speak English, even in the older generations.
We also spend a lot of time in Spain ( I speak reasonable Spanish) and we find fewer people speak English there outside tourist resorts and most business in still conducted in Spanish.
Also, outside Germany and Austria apart from a few bits of Africa German isn’t the native language, whereas most of Latin American speaks Spanish.
I’m biased because I love Spanish as a language but despite speaking it well as well as French I do find German quite hard.
I would just let your dc decide

You don’t always study a language based on the number of people who speak it. Sometimes you study it for the literature and the culture. When choosing a second language, my DD took these factors into account. She did MFL at degree level and liking the country of the language you study factored quite highly in her early deliberations at school.

I have no idea whether Spsnish is easier than German, but I would look at the GCSE results the school gets in the languages. This might indicate good teaching. DD chose Italian partly because the teacher was outstanding. That can make a huge difference!

Spanish, easier than French and the two have many similarities. German is a dying language.

Spanish. Much more widely spoken. And easier than German I think.

I took Spanish. I have no knowledge of German at all, but did find Spanish very easy, very logical language in my opinion, very few irregular verbs etc, so once the basics are understood it should be plain sailing. I also did Latin and think that helped.