Old HDB but mature estate vs New HDB and developing estate

Asking on behalf of my single dad (age 60). Our current house valuation is approx 4 room 400k, 20+ years. Our current place is fully paid.

We want to make a move but am struggling between a convenient location (central near MRT) and cheaper house 3 room VS an affordable newer 3 room flat (<10 years lease)

Friends have told me that for older HDB can either look for near MRT so we can rent it out easily in the future. (Downside is just older house and shorter lease)

What’s the worst that could happen for a matured estate housing that has less than 50 years lease left? En bloc/claim back by government? I'm just worried at the end of the day whatever we have paid for we will not get it back when it's claimed back by the government (when it hits 99 years).

And also wanna ask what would you all do if it’s your parents?