Investing large fund - thoughts?

[zico]

I'm investing about £200k of my father's money who is aged 88 and doesn't need an income from this money, and even in an emergency he's very unlikely to need all of the cash in the next few years (and if he did, I could make up all of this money through other investments) - so immediate access isn't required. As he's fairly risk-averse, up to now I've been investing the money in various 1-year fixed rate bonds and some in NS&I index-linked bonds (though one of these is coming to an end and will in future be based on CPI, not RPI) and the fixed-interest rates are getting worse than ever in real terms, so his money is being slowly eroded in value.

My goal is to protect (and ideally increase) the real value of his money, but without taking on high-risk investments, but feel that my approach has been over-cautious.

I'm now considering whether I should be diversifying - perhaps 50% in fixed rate, but also with 40% in bonds and 10% in pref shares. Possibly also I should be allocating a % of the total to buying tracker funds, to help diversify and maintain/increase the real value of the capital.
Grateful for any views/suggestions/comments.

[todthedog]

This is worth a watch

https://www.youtube.com/watch?v=vaMiLFANFaU

If not the usual life strategy with equity dialed back or a diy mix of global bonds and global equity.

Nice problem to have