I want to call my wife (in India) on a visit visa of three months. Due to my current employment situation, I am not able to prepare Verpflichtungserklärung (sponsor statement). Thus one of her relatives in Germany would be able to make it.

My questions:
Would it be fine that she would give the reason to visit me and present the Verpflichtungserklärung by some one else?
How probable would be rejection/acceptance in such a case?

Alternatively, I would like to call her on student visa (Language course). But I guess just a language course admission would be risky (as her current degree in chemistry may not give an impression of German language learning plans further on). It may still be important to show the concrete plan (study plan after language course).

I appreciate any suggestion
Regards

Reformolating:
If my wife apply for a visit visa (to visit husband) and present a Verpflichtungserklärung by her another relative in Germany.
Would it be fine or may get problomatic?

Regards

As long as you do not withhold information or provide false information, it will not create any problems.

Let your wife explain your situation with the "Verpflichtungserklärung" of your friend and tell the embassy people that the actual purpose is visiting you. She can attach your bank statements and that you have more than 24m2 house. It is better you state this in the cover letter.

Maybe the embassy people might oblige. If your wife has travelled abroad before it might help.