Use Electrum instead of bitcoin core is the best advise I can give.
Not that good advice. Electrum is thin client instead of full node.
It is like suggesting to take Metro to a guy who is complaining that his car is going too slow.
Which might be the correct suggestion if the guy doesn't understand what the Metro is or why he might want to take it.
A better response though would be to find out WHY the guy chose Bitcoin Core in the first place? Does he really have any interest in supporting the network with a Full Node, or did he just want a simple wallet and thought that "Bitcoin Core" sounded more official?
Here's another analogy for you...
Perhaps he acquired a safe with walls of 20 cm of steel and 3 feet of cooncrete, as well as an entire staff of armed guards, and a complete home security and monitoring system so he can protect a plastic toy that can be replaced with $5. Now he is complaining about how long it is going to take to install all this security, and someone suggests he just cancel the contracts and store it in a free safe that he can find on craigslist.
MANY people spend more on bandwidth and storage to operate a Full Node than they are actually storing in the wallet itself. If they WANT to help the network, that's great. But, if they just don't know any better then they may find that they MUCH prefer the experience of using a simpler wallet.