TTC With age gap - will our baby have problems?

I am 21 years of age and my boyfriend is 51 (no hate please). We have been together for 3 years and he is my world, I love every ounce of him (no pun intended, wait till you hear the next part,)

I am 8 stone 6 lbs and he is roughly 25 stone. He has lost a bit of weight since I’ve met him and I am so proud. He has had a pretty stressful life, when he lies in bed of a night I can see the tears swelling in his eyes, he hugs me and doesn’t let go. We are made for each other, I’m adamant.

Thing is, as I mentioned:

He is an older parent (which shouldn’t cause any issues because let’s face it, so many men (celebrities & men I know personally) have had children in their 50s/60s/70s etc and the kids are fine. My parents were 42 when I was born.

My SO is obese... this is the part which concerns me. He drinks quite a bit too, contributing to the extra pounds. We are thinking about trying to have our first child, I’m speculative at the moment however and I don’t know what the risks are if we managed to conceive?

He isn’t 100% healthy - I’m in tip top shape. I guess we will never know if we don’t try, and our son/daughter could be possibly be absolutely fine, I just want to know from your experiences/ what you have heard/ what you know. Thank you

& also, if it turns out we could conceive a child with health issues then I am not going to take a step further in trying to have a baby... i would be so distraught, beyond words cannot describe how upset I would be. I love my man so much but I feel as though it’d break us apart if we couldn’t have a child.