This is very up to chance. Sometimes the VPN works, sometimes it doesn't. Sometimes it's fine on the home Internet, but fails on the cell data, sometimes it's otherwise. And it is fine if you're somewhat tech savvy and okay with tinkering with settings, but a huge pain for the older relatives.
Yes, indeed, it is still possible. Right now RKN introducing new DPI capabilities at TSPU(govt filtering hw/sw stack mandated at ISP) - proactive host probing/scanning and mandate for russian services to check and report VPN users hosts. I.e. you use e-shop app and it will report you Nehterlands VPS IP if detected, including split-tunneling tricks)
Won't they just be able to identify the traffic at his local internet provider as being suitable for a VPN usage match and send 'law enforcement' over?
I'm sure you're able to drive faster than the speed limit as well. The issue isn't whether technical circumvention is in the realm of possibility. The base issue here is that even so called 'democratic' governments seem to be copying the authoritarian playbook when it comes to cracking down on privacy online.