I thought I would look at this. Numbers are a bit clumsy. I have probably got something wrong, but in my mind.
If a 500k flat with 10 percent deposit was purchased at an interest rate of 2.5 percent 5 years ago. That would be approximately £2000 pcm. I appreciate the interest rates are now more than that.
After 5 years they will owe 380K according to MSE mortgage calculator. Presuming there is no increase in property prices.So they will have equity of 50k initial deposit and 70k.
They will have spent 2000x60 which is 120k.
So will leave with 50k. Costing them 70k for the 5 years.
Now if they were to sell they would need fees say 5k. Only would need stamp duty if they bought again.
Now the price of rent is what impacts the calculation. Estimate at 1500 rent pcm. It will likely be more but the total payment is 90k.
So if they were to leave after 5 years and start afresh with the mortgage they paid out 120k made 70k back. ( won't include the deposit) so have cash of 50k. So total cost of the 5 years from their pocket 70k.
Renting at 1500 cost them 90k
Renting at 1000 would cost them 60k
Renting at 2000 would cost them 120k.
So there is a point it is cheaper. I am just not sure rents are that cheap. Maybe they are.
Now if the house was to lose 100k in value for 5 years. Now it has cost them 120k minus the loss in selling so they would make 20k. The whole 5 years has cost them 100k.
Now if they stayed as a forever home. A mortgage of 450k for 25 years would cost 605k. After 25 years you would own this 500k property. Presuming no increase which is unlikely so cost 105k. All appreciate your relatives get the locked in 500k as you need a place to live. The cost of a home hs stopped and you are now sheltering for free.
The rent would cost over the same period ( presuming no increases, again unlikely)
at 1500 pcm is 450k
at 2000 pcm is 600k. Then you still need to pay it after 25 years.
Long term buying seems to be better. Renting only short term and if can get cheap rents. Seems more economical.
Now preferances of not being locked in etc or being able to decorate without permission on the other hand. I get that but financially it really depends.