There are numerous routes to take, but assuming you want value for money, you'll want to go modular.
For this the three most common routes are:
1 Modular in the UK. (Expensive, weather dependent)
2 Modular in the US all the way, then convert. (Lots of extra learning)
3 Get a PPL and hour-build in the US, then come back and do the serious bit in the UK. (My preferred route)
By far and away the biggest hurdle to getting a PPL in the UK is the weather - aircraft will be booked solid on flyable days so a PPL could take many months. Go to CA, FL or AZ however, and you won't have that problem. I flew 2-3 times a day when I did it and a PPL in 3-4 weeks is entirely possible. When you'relearning to fly, waiting is soul destroying!
When you learn in the US, you have two options: FAA or EASA PPL. It doesn't matter which one you get, as it is just a stepping stone. The sensible choice is definitely FAA (I know this because I did EASA!)
An FAA licence has 1 written exam, an Oral and a flight test (which has a few extra bits) whereas an EASA licence had 7 exams, (I think it's now 9) and a flight test.
Here is the important bit: an FAA PPL is issued on the spot, which means that hour building can be done with friends and family. Or Hooters girls. With EASA you have to send off to Gatwick to get your licence issued before you can fly, which means all of my hour building was done solo. Without Hooters girls. I'm a pilot, which means I've never grown up, so I can put myself in his position. I'm sure he'd rather fly twice a day than once a week! The other thing to consider is that 3 months in the US will be a great experience!
As for the CPL it should be done in EASA airspace, to get used to charts and Navigation, and the IR has to be done here anyway, so I'd suggest diamond flight academy (others are available) to get that lot done in 2 months. The only other thing I'd recommendis to avoid "empty" hours and get as much Instrument and night hours as possible, and an FAA IR will help towards an EASA IR (my biggest regret was not getting one when I had the hours to burn) There are pros and cons to everything, so expect the next post to be the complete opposite!