Is my repair guy trying to scam me?

So I had an MSI GT72 2QE laptop, but something went wrong with it. Over the past few months, the DC pin on the charger would get burning hot and the laptop would flicker between charging and not charging randomly, but at other times it would be completely fine. I now realize this is something I should've looked into, but I let it happen too long. One night after I unplugged my laptop, it refused to charge again the next time I tried. I tested other chargers, different outlets, etc and it still didn't work. I took it into a shop and they told me the DC jack's connection to the motherboard is probably loose or the solder lifted. So I took it to a repair guy with great reviews and lots of recommendations. Here's where it gets kinda iffy, at first he said it's probably the DC jack but he'll take a look at all the circuitry to make sure there aren't any shorts. Later on he called me saying that the faulty connection resulted in a 19V charge getting through to the 5V and some otherV chip and blew them, so he had to get new ones and it would be fine. A week later, he tells me that there's a chance that the CPU is fried, but he's going to replace some other chip and see if the CPU is okay. So now I'm here waiting; what I'm curious about is the fact that my laptop was still working perfectly fine on battery before the battery died. If the faulty DC connection fried a bunch of chips and the CPU, wouldn't it have been affected prior to the battery dying? I asked him this and he said sometimes these things only affect the next startup, but that doesn't make sense to me.

Just want to get some insight as to whether he's just trying to milk me for some more money because, if so, I'll get my laptop back and take it elsewhere. Thanks, in advance, for the help.

tldr; laptop dc jack stopped working, battery died, now repair guy is saying cpu might be fried even though laptop was working just fine before the battery died. Is this possible?