It certainly isn’t clear but surely as the money is being paid from the U.K. pot the funds for over 65s will still be coming to the Scottish government.
But isn’t the whole point of devolution, that no matter where the money comes from, on the matters devolved to the Scottish/Welsh/NI Government/Assemblies, it is upto the them how the money is spent?
If the MSP’s/AM’s/Stormont decide to spend the received revenue on other things, it is upto them.
Similarly with the NHS where Scotland, Wales and Northern Ireland’s devolved Government/Assemblies decided to make all prescriptions free of charge out of their allocated budget. In England, the UK government still imposes prescription charges (unless one is exempt).