Learn French: Le dirigeant est sévère, mais je songe à lui. - The leader is strict, but I am thinking of him.

The verb songer à belongs to a special group of verbs that don't allow you to put an indirect object pronoun (like lui or leur) in front of the verb when referring to people. Instead, you must keep the preposition à after the verb and follow it with a stressed pronoun (lui, elle, eux, elles).

If I were thinking about a new rule instead of the leader, would it still be à lui?

No. When non-cliticizing verbs like songer à refer to an inanimate object, an idea, or a situation, you drop the à and use the pronoun y before the verb. So, "I am thinking about it" would be j'y songe. You only use à lui for people.

What is the difference between songer à and penser à?

Both mean "to think of" or "to think about", and both follow this exact same grammar rule for people. However, songer à is a bit more poetic or literary. It often implies musing, daydreaming, or considering something deeply, whereas penser à is your standard, everyday verb.

Does sévère just mean "severe"?