Envieillir belong to the 2
nd group.
Envieillir is conjugated the same way that verbs that end in :
-ir
Envieillir is conjugated with
auxiliary avoir.
Envieillir verb is
direct transitive.
French verb envieillir can be conjugated in the reflexive form:
S'envieillir
Envieillir verb is a direct transitive verb, so passive voice can be used.