It's been a long time since I glances at Fire & Ice. So are we talking about the Elemental Summons list, page 26?
If you are looking for advice on how to keep things from getting out of hand, then I say:
Looks like the Elementalist would have to cast Summon Whispling (level 3) and then Control Whispling (level 4). If he summons five whisplings that would be 35 PPs and ten opportunities to suffer some sort of spell failure.
So, first step is to make him roll those SCSMs. Also, 35 PP is a lot to a 5th level caster, so don't be too loose with the spell adder and PP multiplier items anytime soon.
At 5th level those whisplings are going to have to stay close (within 25') or they will be freed from the spell bond. If this happens there is a 50% chance they attack the caster instead of returning to their plane.
How often does he have to release and summon more elementals? In my game if a guy came into most villages/towns/cities surrounded by elementals there would be potential trouble.
As for an air whispling's capabilities...
Without any guidance from the whispling's description, I would rule that they couldn't carry more than a few pounds. (2# per level = 2 pounds, for example). Not a very effective pack mule. Maybe an Earth whispling could be stronger?
The book mentions a whispling forming "pseudo-pods" to attack with, so I would rule that its manipulation is limited. Opening a door if it had a simple latch, but lock picking would be straight out!
Keep in mind, the player may have an "Elemental Summoner" archetype in mind for his character. If that is the case, he does one thing and expects to do it well. If you go above and beyond the rules to nerf the character there could be hard feelings.