Since the telepathic link is listed under the languages section of the stat block, it would seem to me that it is as limited as normal speech in the amount of information that it can convey. It just isn't audible.
Telepathic Link (Su) A homunculus cannot speak, but the process of creating one links it telepathically with its creator. A homunculus knows what its master knows and can convey to him or her everything it sees and hears, out to a distance of 1,500 feet.
So, the master cannot see through the homunculus' eyes any more than he can see through the eyes of the party's fighter. The homunculus can indicate telepathically where an object or creature is but that likely only indicates the basic location, not a specific location, which isn't good enough for targeted spells, but would be fine for area spells.
the Bestiary also says about telepathy:
Telepathy (Su) The creature can mentally communicate with any other creature within a certain range (specified in the creature's entry, usually 100 feet) that has a language. It is possible to address multiple creatures at once telepathically, although maintaining a telepathic conversation with more than one creature at a time is just as difficult as simultaneously speaking and listening to multiple people at the same time.
Format: telepathy 100 ft.; Location: Languages.