Owning the A7RII doesn't mean you have to maintain an additional line of gear (batteries aside, perhaps). Although my own A7II (paired with the LA-EA4 adapter) sometimes acts as a backup body for my A-mount Hasselblad HV, the vast majority of the time I use it for adapting older manual glass from a variety of mounts, but especially M42 and K-mount (some of which I previously used with my K-3). As I've stated before in these forums - and I mention it in my signature - I don't own a single native E-mount lens.
With a couple of inexpensive mount adapters for your incoming A7RII, you'll have an incredibly capable manual focusing, vintage lens platform. I realise the last thing you need is more glass - given the wonderful collection you already own - but it's great to be able to use older full frame lenses without cropping to APS-C format, and to nail focus every time without guesswork.
Since you'll be keeping the camera for a respectable period out of courtesy to your generous Dad, I'd really encourage you to try adapting at least your existing manual focus lenses. I think you'll enjoy it. If not, at least you'll know
If, once you've tried it, you decide it's not for you, I'd be tempted to suggest selling it and buying a K-1 or K-1II as an additional body to enjoy with your existing full frame K-mount glass (no need to buy the big, heavy f/2.8 zooms or latest fast aperture primes unless you particularly want to)...
Last edited by BigMackCam; 11-08-2020 at 06:46 AM.