Let's see:
- Leads an criminal organization
- Teams up with ex teammate to take over the world
- Has a son whom he wants to see at parties
Doesn't look suicidal to me.
Hes going for a war against the world because its the highest chance of him dying a viking death. I think that before Oden, Kaido had a viking sense of honor( ie only respect the strong) but lacked their drive to want to die gloriously or alteast had it to a lesser degree. But after witnessing oden's death, i think he grew to admire it and even glorified death. Thats when he started going around challenging yonko and marines, because he wanted that. Kaido has honor, a lot of it in fact. But its not samurai honor, its viking. Its why he had no problem trying to kill momo and others he viewed weak. Even oden, at first kaido viewed him as weak minded and a fool. But after the boiling he grew to respect him immensely. Both were wary of each other anyways, but kaido less so as he seemingly was stopping an enraged oden from gutting orochi in the castle for a good while up until oden was forced to accept the deal of him dancing until kaido and orochi leave.
He was too arrogant in believing that since he handled him just fine in his human form that he would be fine in dragon form too, fatal mistake. As it allowed Oden to injure him greatly.
I mean there is a reason Oden wrote what he wrote to toki and why at first he wanted to kill kaido in his sleep/drunk( the same strategy they're trying to do now btw haha). Thats because he wasnt sure he could take him. Then the man went on to get even stronger and became the yonko we know right now. Big mom hypes him up, Blackbeard hypes him up. Oda hypes him up. I fully believe there is a reason Oda made him say what he said( that he is bored of life and wants to create the greatest war this world has ever seen). Its because something is going to happed in the onigashima raid that will trigger a huge war. The same way ace's defeat did in marineford.
So yes, kaido is suicidal. Running an organization to get weapons and troops to wage war and trying to take over the world doesnt detract from his wish at all.