I would talk to your children about the need to be careful of other people’s feelings. You know you are overweight and their comments are unnecessary and hurtful. I wonder if your children are heading towards a problem with their weight too?
It is difficult when you have reduced mobility not to overeat, even if you ate the same as before you would put on weight, without the additional problems with the drugs. I would have a look at what you are eating and buying and reduce your portion sizes. Easier not to eat the chocolate biscuits if there are not any in the house, rather that have to resist them when they are sitting in the cupboard. The MS Society has an exercise DVD that you could do at home. You may not feel up to it, but with exercise you often feel better after, even you did not feel inclined to start. Try to make it part of your routine. Remember it all adds up.
Also speak to your doctor about what help might be available. Not much point in telling you that you should lose weight if they dont offer you and help an or advice.
My normally slim husband who has SP has been doing all of the above and has had some weight loss. It is slow, but better to lose a couple of pounds, rather than put them on.
If you do manage to lose some weight your will feel better about yourself and your may well be easier to manage, so keep that in mind.
Good luck!