I've been following it recently, but there's a lot I don't understand.
He committed fraud by stealing charity donations and keeping the money for funeral plans. Both are very risky, I would have thought - just takes one family to check with a charity that they'd received the donations to get found out.
But how did he gain anything by not conducting proper funerals? Presumably funerals were held so he'd have to pay the appropriate fees and costs anyway.
I was following along with the BBC coverage of the trial the other day. But it sounds like there were indications they were reusing coffins for multiple people during viewings and possibly funerals. Some families also noted they'd paid for a mid-range coffin but their loved one's coffin during the viewing seemed much cheaper. Some family members had even said that they didn't actually think their loved one was in the coffin during the funeral because something just felt off.
So while they were doing some actual services which will have had costs, they were still clearly pocketing some of the money rather than paying for the expenses the families had been charged for (like coffins, cremation costs, cold storage, etc). They were also charging considerably less for their services than other funeral directors in the area, so they might have only been offering the viewing/wake services and Legacy would 'handle' the actual cremation separately at a later date.
But then they were likely actually just taking a body back out the coffin to reuse it - so say, they'd received payments for 5 different coffins but in reality, they've only ordered 2-3 and reused those while pocketing the rest of the money (meaning you've then got 2 or 3 bodies you can't get cremated because that money's been spent on holidays).
They were skimming off the top but because they were putting on an excellent caring front during these funeral services they did provide, it meant people had enough goodwill not to question things even when they were having issues with collecting ashes, etc.