I am not quite sure what you are hinting at. Could you please clarify?
The only large-scale aid Germany is providing to other EU countries I am aware of are their (internally not disputed) EU contributions. But if I remember correctly Spain is not a large net receiver from those contributions either (barely a net receiver). Also, Germany could not change that without leaving the EU, so I am not sure how that would be any leverage.
I mean the realpolitik of increasing the EU budget, currently for the aid for Ukraine. (If I'm not mistaken.)
Back after 2009 the whole discourse was about bailing out the southern banks, of course not via direct aid, but via ECB operations, standing up various credit/emergency facilities, basically anything that leads to more gross EU credit risk (or risk sharing).
The only large-scale aid Germany is providing to other EU countries I am aware of are their (internally not disputed) EU contributions. But if I remember correctly Spain is not a large net receiver from those contributions either (barely a net receiver). Also, Germany could not change that without leaving the EU, so I am not sure how that would be any leverage.