Being an apl Prof. still needs to go through
a committee, to show your research
and at end needs to be approved by the education minister of
the state.
I do not believe that he was an apl. Prof.

BTW, PD 有资格带硕士 and also 有资格带博士.
You may not meet such a case, this may be just because
PD has no position (or 1/2 position) to offer to a Ph.D candiadte.
If a PD has a position (or 1/2 position), for example from DFG,
then he can have a Ph.D candiadte.