What do I need to know and what should I do (comp security)?

Hello. I have never used reddit before but I figure this is a good place to get some quick help.

My dad just fell partial victim to one of those phone scams. He received a popup that he couldn't close and proceeded to call the number on the screen. I believe he allowed the person on the phone to access his computer. He was directed to a website where he input some numbers. The person on the phone then began to draw a house on his screen (why is not important). My dad gave the scammers his email address but not any passwords. He eventually realized he was being scammed and hung up. He then left his computer on for a few minutes and within about 5 minutes took out the battery (it was a laptop) and disconnected everything from it. He has not turned it on or accessed his email since that time. He did not give any credit card info or other personal information.

I tried to find out information on this scam but I couldn't find a sufficient amount to dispel any concerns I have. I have some questions I hope some of you can answer.

1.What has most likely happened to his computer. Did the phone scammer download programs onto his computer. If so, what type of programs?

2.Is it possible the scammer accessed information already stored on his computer? Could he have accessed programs on his computer and downloaded/looked at them?

3.He is calling some computer security experts tomorrow. I'm wondering: what are some big problems you see with this scenario and any immediate actions that should be taken? Has information on his computer been seriously compromised or were malicious programs only downloaded onto his computer? Speculation (so long as it is probable) is welcome.

4.Could other computers on the same internet network be at risk or already been compromised?

Also, what would be the proper subreddit to put this post into to get good answers?

Thanks

/r/AskReddit Thread