Chestnut
Do not attempt to lift him using painkillers, you may do your back a worse injury. You will be tempted.
Let him get used to you from the floor, as you sit engaging with him, smiling, waving, holding out toys for him to come and get. Let him come to you. If he sees a friendly smiling face offering him some interesting toy he will want to come over. Once he's used to you maybe he will sit on your lap briefly, especially at a table where you can turn him towards a jigsaw or whatever on the table, holding and cuddling him whilst he does some activity. The important thing is not to force him. Let him take the lead.
I'm sure you will get plenty of time engaging with him face to face and enough cuddles to keep you satisfied! Don't forget to take some interesting toys to engage his attention, but check it's something he hasn't got.
Super advice. A gran who is interested in him, and doesn't have to rush around doing things...why, thats something to look forward to.
If you persist, then they might just want to snuggle.
