The prospect of liquid THC is very possible as it is widely used in the US in states that have legalized it (Colorado) or medicalized it (California, Montana ect)
It is extremely dangerous (like the point of explosions that can destroy your home and those within shouting distance) to extract THC and is not something that should be done at home or even thought of attempting.
Since you can't get it here and it is illegal (all though decriminalised) the possibility of obtaining any is probably very low.
If they want to avoid burning with papers ect, they should look into herbal vapourizers which are not the same as Ecigs and are very very different. Or just get off of tobacco completely and get an ecig
Unfortunately, this forum isn't about those kinds of vapourizers but there are other sites out there that could point them in the right direction