This OA defies Standard English usage. With all due respect, the justification given my Mike is invalid. Here is why.
The word "some" can be used as a pronoun, a determiner, or an adverb.
For example:
I ran into some weirdo on the street. - determiner (used to refer to an unknown entity. For example, an unknown person)
I made some money, selling lemonade. - pronoun (used to refer to an uncertain amount)
In this question, we are using the word "some" as a standalone pronoun. Yes! Most, Any, None, All, and Some can take a signular or plural depending on the noun attached to these pronouns.
For example:
Some people are dishonest. (people demands the plural usage)
Some money is missing. (money demands the singular usage)
But if the word "some" as a standalone pronoun is used to specify an uncertain number of something from even a particular collective group, it should be used in the plural as it is "an uncertain number" and the uncertain number definitely isn't singular because if we want to refer to one, then we just have to use "a" or "an"
For example:
Most of the class was happy with the lecture. (in this sentence when we say the class is happy, logically it's not the physical classroom that's happy but rather the members of the class as a collective.)
So if we write,
Most of the class was happy with the lecture, but some were unconvinced.
We have to use the plural "were" because we are referring to some unspecified number of class members who were unconvinced.
In the OP, the university's faculty is the body of faculty members. So if we use a standalone pronoun "some", it would logically refer to the few members of the faculty who were willing to extend him a civil welcome.
P.S. Some is not a pronoun like he, she, it, they for which we use the singular plural noun pronoun matching rule.