my laptop charger wont work?

If his laptop is a different brand or model, then it probably wouldn't work. Here is an excerpt from a online charger site:

Will This Charger Work For My Laptop?

The following three condition should be met for you to use this charger safely. You can contact us here if you need further assistance.

1) Output Voltage is within +/- 5% of your old charger's output.

For example, if your old charger provides 19.5V, then you can use a charger that provides 20.5V or 18.5V.

2) Output Current is the same or higher than that of your old charger.

For example, if your original adapter provides 3.42 Amps, then you can use a charger that provides 3.42 Amps, 3.9 Amps or higher.

3) Connector tip must fit securely into your laptop.

So make sure all those are checked and then continue. If they aren't on the other hand, you would need to purchase one because using the wrong charger may damage your laptop and it could even kill it completely.

I would also like to suggest purchasing from http://www.topmic.com/ like I did in the past. They provide shipping and lifetime warranties for free, as well as a 30 day refund period. They aren't the cheapest online store but their service makes up for the few extra bucks.

If you have any further laptop questions, feel free to ask. I'll do my best to help out.

Once again: http://www.topmic.com/

You can look up the laptop brand, model, and model number on the top right or search it on the top left.

Best of luck.

Does he have an HP? Sometimes the polarity of the charger's output is set for one brand of laptop but it won't work in another laptop. I have an ACER laptop and when I bought it to replace an old HP laptop, the HP charger would not work in the Acer.

Bottom line, the correct polarity must be used. Your laptop may be incompatible with your brother's.

Without knowing the make of his, I can't tell.

you might have a bad system board or the pin on your DC-in might be broken.