If you were a soul-mate type of friend where you can tell them anything and everything then I think it can work because you would love that person as a person and it can even be the unconditional type of love that one would associate with a partner or child but not necessarily the Eros type of love that one might insist upon when younger.
On the other hand I also find seeing an older couple who are obviously in love and still desire each other after 20 or 30 or even 40 years together I find much more erotic that seeing a couple in their teen or twenties all over each other. That certain look that the older couple give each other accompanied with a squeeze of the hand or peck on the cheek can convey so much more and is often done unconsciously and without any embarrassment.
"I think it can work because you would love that person as a person and it can even be the unconditional type of love that one would associate with a partner or child but not necessarily the Eros type of love that one might insist upon when younger."
Yes, I'm saying just that. Romantic love is not a "must". The older you are the more you realize that. It's nicer that way, but not all important.