Hi, Ray,
Sorry to hear of the trouble with the cross and especially sorry for the family loss.
You didn't state any info about the type of wood you used but, in most instances, I would try
helmsman spar urethane. It will gradually amber most woods but, it is one of the best
finishes or most highly recommended finishes I have heard of.
It may be necessary to try to periodically put another coat of urethane or water sealant
if at all possible since I see this one only lasted about 6 months,.
Thompson's waterseal comes to mind for that treatment rather than layer after layer of urethane.
Of course, if you can keep the base off the ground to keep it from absorbing moisture would be
a great help but, I realize sometimes that just isn't an option.
Keep us informed about what works best for you so we can benefit from your experience.
God Bless! Spirithorse