They should only invest in a flat/property if doing so is financially advantageous. So, if they would be paying 1100 in rent but can afford 1200 on a mortgage, then yes it should be considered. But they need to cost in additional costs - a bed, sofa, cooker/fridge and washer/dryer as the essentials. Can they afford this on top?
re whether flat/house - they need to speak to an estate agent and consider their local market? PPs have been dismissive about flats and leasehold - no need to be as they are ideal first time purchases, or even downsizing ones so there is always a market - in London for example 90% of the properties on the market are flats. Noone would live in London if everyone ruled out flats - I suspect the same is true of many cities. We are in the process of buying a city flat with 997 years leasehold in a new block - perfectly fine but obviously needs different legal checks as part of the conveyancing, especially post Grenfell as they do additional checks on building over 5 floors/11.5m in height now.
A house can come with much more upkeep and maintenance (garden, roof etc all need to be maintained and financed by the single owner - whereas the costs are shared in a leasehold/flat arrangement that has been paid into over several years to ‘save’ for these expenses). A flat, esp a new one, can be perfect for a young person who works long hours and has a social life - and doesn’t want to spend all their weekends cleaning and decorating.
Right now is a buyers market with some good bargains. Interest rates seem to be on a slight downward trend so a mortgage deal now would be pretty fair. So my advice would be to speak to an estate agent, look at what is on the market - look at what has been on for a while and been reduced to get a sense of what is not selling - and monitor it for a few months to see which type of properties seem to get snapped up. Perhaps agree a mortgage in principle now (the offers are usually valid for 6m) just in case your YP spots a bargain. But I reiterate - it’s only something to be entered into if YP can truly afford the additional costs associated with it - I am guessing that sites such as Money Supermarket may have a spreadsheet to do the calculations, so I’d start there?