Actor and comedian (who tragically also died by suicide) Robin Williams once said "I think the saddest people always try their hardest to make people happy because they know what it's like to feel absolutely worthless and they don't want anyone else to feel like that." So it doesn't surprise me that Thomas Kingston would have a happy veneer in spite not feeling that way on the inside.
Depression is a truly insidious disease. It exacerbates negative experiences and warps positive ones into negative ones. It convinces people that their loved ones' lives would be much better if they weren't in it, that they're doing the world a favor by taking their own lives.
Of course, it's the exact opposite. Unfortunately, Thomas's loved ones will spend the rest of their lives combing over every word they said to him, every action they did, every sign they've might have missed, anything to retroactively save his life. The death of a loved one to suicide is one of the worst things that happen to anyone. My heart goes out to Lady Gabriella along with the Kingston and Kent families, and I hope they have all the help they need to process Thomas's death in a way that's not self-recriminating.