"Well, three of you already have it and Scott has a innate spell, which does healing, but it is infinite healing regardless."

"Most bad guys don't want infinite healing, they want infinite regen. Unless it does that too?"

"As long Scott is conscious and able to speak he can cast the healing on other people indefinitely. So, pretty close."

"It won't let Scott heal himself if we can keep him unconscious, though. We can do that."

"You have a safe way to keep him unconscious for long? I... actually not sure what your strategy is in here."

"Yeah, that's easy. Lydia does it. And if she goes rogue, Scott does it." 

"How does that work? And wouldn't it make them more vulnerable? What if both of them go rogue?"

"They won't. If they do, we can handle that."

"Alright... this means no one wants spellcasting?"

"Maybe. Maybe it means we have to be really careful?" 

"Lydia and I shouldn't learn more than we have. The rest of you can judge what's safe." 

"I want cool magic, and I'm human and super fragile so if something goes wrong there's no problem." 

"You already have basic spell-casting. I guess you could get hallowed vows, they aren't that much of a strong tactical advantage."

"Sounds good to me. Explain hallowed vows."

Henry explains how they work again. It takes some dedication to get anywhere fast, but they can work out something suitable for individual capacities. Despite Stiles' lack of focus, Henry's hallowed vow should suit him well enough.

"Let's start now. How much can I control what I get? Are there some things that are worse to try for?"

Stiles can get a large amount of control, he can't influence efficiency, but Henry can guide him through the process of creating an optimally efficient vow under the circumstances? Is he interested in a slow steady but permanent sensory boost or limited use peaks? Normal senses or magic detection? Henry might even be persuaded to let Stiles acquire a mild aura of "I am a highly educated scholar".

Henry puts a hand around Stiles' waist while explaining this.

Something broadly useful, large-scale, limited power. Can he get weak telekinesis?

He squirms slightly at the touch. 

Not with Henry's hallowed vow, but... Henry retrieves a book and pages through it. He needs to remove the hand temporarily to do that, but replaces it with a soft wing while does so and then keeps both hand and wing on Stiles.

So, there this archangel - a woman whose alternate form had fifty hands floating around her each one with an eye on the palm - whose hallowed vows gave telekinesis in exchanging of learning how objects worked and how to make them (ideally with said telekinesis), which is approximate enough to Stiles' curiosity that should work.

Henry makes some conservative estimates. Giving how much time he invests on learning everything under the sun even without a particular order... Stiles can get a daily "charge" of telekinesis that is as good as his own ability to move objects around (minus, you know, having to actually touching them) and lasts one or two minutes per day of investment. Meaning, that this would start at 1-2 minutes after a day with the vow, 7-10 minutes after a week, an hour after two months and after nearly three years Stiles will be able to keep the telekinesis on all the time.

"When can I start?"

Scott is talking quietly with his pack.

Right now is good, it is going to take some time studying/researching until he gets benefits. Henry asks for Scott helps (by easing off the pain and applying the healing spell) to remove one of his own feathers, then Stiles will be guided through making the hallowed vow that Henry wrote (it is specifies gains and efforts and almost feels like a contract. Stiles can feel the words having a magic power that settles gentle in his soul like a seed eager to germinate after being watered with knowledge. Henry kisses him when its done. "Congratulations."

Stiles is really enjoying his life right now. 

Henry is entirely happy with making Stiles' life happier.

"So, anyone wants to go next?"

"I'm up next, I have seniority."