change ausbildung visa to student visa .

In principle yes, he can apply for a student visa again.

But the processing officer will certainly question his dedication to studies, after he terminated his first attempt at it - and now wants to abandon his apprenticeship as well. If they have the impression that he isn't serious, just wants to find ways to stay on in Germany, then they will of course reject the application.

    My son went to Germany with a student visa for a studienkolleg course and he changed to an ausbildung (apprenticeship) visa later. Now he is trying for a bachelor's degree course and If he gets admission to a college/university, can he change his ausbildung visa into a student visa and join to university without completing that ausbildung?
   

    -@lalu lorance

A critical question is if he finished the Studeinkolleg since it is a prerequisite for people to do a bachelor if they don't have the level of the German Abitur needed for acceptance. An Ausbilduing (vocational training) is not a substitute. He has to finish either the Studienkolleg - or usually do 2 years of university at home before getting into a bachelor in Germany. This would be 2 years of a bachelor or maybe an associated degree would qualify.

And language skills are still a major factor. The vast majority of bachelors are taught on a C1 level German. Most of the exceptions, the ones offered in English are at private universities, which tend to charge 8 to 10 thousand euros/semester for tuition.

Most masters are taught in English even in public universities where while tuition-free for EU-students, they are not necessarily so for non-EU one’s. It totally depends on the program. Cost can range from 0 to 8,000 euros/semester. And yes that is public not private universities. While one might find an exception, the idea that a non-EU student can get a tuition-free degree instructed in  English is rare.

If I go germany on Ausbildung visa, Could I change my Ausbildung visa to student Visa having reached in germany?

@Rao Mujeeb Please read the above replies and other discussion threads about the same topic. I believe it has already been exhausively answered. But if not, please come back with detailed questions that weren't addressed yet. Thanks for your understanding!