This is the 13976th most frequent Spanish word.
sucederlo
To succeed or follow him/it.
Here, 'sucederlo' is used in the form of a verb infinitive with a direct object pronoun (lo), referring to 'to succeed him' (e.g., taking his place or position).
Es probable que sucederlo sea un gran desafío.
It is likely that succeeding him will be a great challenge.
In this sentence, 'sucederlo' is used to mean 'to take over or succeed an individual,' with 'lo' as the pronoun referring to the individual.
Después de tantos años de trabajo, por fin alguien digno podrá sucederlo.
After so many years of work, finally someone worthy will be able to succeed him.
Here, 'sucederlo' refers to 'a direct action of succession' pertaining to a specific him (object of succession).